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1

Spectral down-conversion in Sm-doped borate glasses for photovoltaic applications  

NASA Astrophysics Data System (ADS)

Borate glasses and borate glass ceramics are good candidates as a matrix material for fluorescent ions like samarium. The chosen network modifier influences the fluorescence efficiency of the incorporated rare earth ion. Sm3+-doped lithium, sodium, barium and lead borate glasses were examined with respect to their fluorescence properties and potential use as a down-converting top layer of a solar cell.

Dyrba, Marcel; Miclea, Paul T.; Schweizer, Stefan

2010-04-01

2

Devitfrification Properties Of Bismuth Borate Glasses Doped With Trivalent Ions  

NASA Astrophysics Data System (ADS)

Bismuth borate glasses and crystalline phases have outstanding luminescent and nonlinear optical properties; therefore there is lot of interest in their preparation and characterization. In this study we report the crystallization properties of bismuth borate glasses doped with trivalent ions. Glasses of the composition: xBi2O3-(100-×)B2O3 (x = 20, 25, 30, 37.5, 40, 50, 60 and 66 mol %) and 40Bi2O3-1Tv2O3-59B2O3 (where Tv = Al, Nd and Eu) were prepared by melt quench technique and devitrified by heat treatment above their glass transition temperatures for several hours. The crystalline phases produced were characterized by FTIR absorption spectroscopy, DTA and X-ray diffraction. Bi3B5O12 was found to be the predominant phase in all crystallized samples containing Bi2O3 concentration of <=40 mol %, at higher Bi2O3 concentration, we observed the formation of Bi4B2O9 phase. Glasses with Bi2O3 concentration of <=37.5 mol % produced Bi2B8O15 phase on crystallization. The metastable BiBO3-I phase was formed by short duration heat treatment (less than 5 hours) of the initial glass sample. Doping with rare earth ions like Eu3+ and Nd3+ promotes the formation of BiBO3-II phase while Al3+ doping suppresses it.

Khanna, Atul; Bajaj, Anu

2010-12-01

3

Infrared spectra of zinc doped lead borate glasses  

Microsoft Academic Search

The infrared spectra of zinc-doped lead borate glasses (10–30 mol% ZnO) were measured over a continuous spectral range (400–4000\\u000a cm?1) in an attempt to study their structure systematically. No boroxol ring formation was observed in the structure of these\\u000a glasses. The formation of Zn in tetrahedral coordination was not observed. The conversion of three-fold to four-fold coordinated\\u000a boron took place.

S. G. Motke; S. P. Yawale; S. S. Yawale

2002-01-01

4

Devitfrification Properties Of Bismuth Borate Glasses Doped With Trivalent Ions  

SciTech Connect

Bismuth borate glasses and crystalline phases have outstanding luminescent and nonlinear optical properties; therefore there is lot of interest in their preparation and characterization. In this study we report the crystallization properties of bismuth borate glasses doped with trivalent ions. Glasses of the composition: xBi{sub 2}O{sub 3}-(100-x)B{sub 2}O{sub 3} (x = 20, 25, 30, 37.5, 40, 50, 60 and 66 mol %) and 40Bi{sub 2}O{sub 3}-1Tv{sub 2}O{sub 3}-59B{sub 2}O{sub 3}(where Tv = Al, Nd and Eu) were prepared by melt quench technique and devitrified by heat treatment above their glass transition temperatures for several hours. The crystalline phases produced were characterized by FTIR absorption spectroscopy, DTA and X-ray diffraction. Bi{sub 3}B{sub 5}O{sub 12} was found to be the predominant phase in all crystallized samples containing Bi{sub 2}O{sub 3} concentration of {<=}40 mol %, at higher Bi{sub 2}O{sub 3} concentration, we observed the formation of Bi{sub 4}B{sub 2}O{sub 9} phase. Glasses with Bi{sub 2}O{sub 3} concentration of {<=}37.5 mol % produced Bi{sub 2}B{sub 8}O{sub 15} phase on crystallization. The metastable BiBO{sub 3}-I phase was formed by short duration heat treatment (less than 5 hours) of the initial glass sample. Doping with rare earth ions like Eu{sup 3+} and Nd{sup 3+} promotes the formation of BiBO{sub 3}-II phase while Al{sup 3+} doping suppresses it.

Khanna, Atul [Department of Physics, Guru Nanak Dev University, Amritsar-143005, Punjab (India); Bajaj, Anu [Department of Applied Sciences, Adesh Institute of Engineering and Technology, Faridkot-151203, Punjab (India)

2010-12-01

5

Synthesis and structural studies of praseodymium doped silver borate glasses  

SciTech Connect

Praseodymium doped silver borate glasses with nominal composition xPr{sub 6}O{sub 11}-(25-x)Ag{sub 2}O-75B{sub 2}O{sub 3} (x=0, 1, 2, 3, 4, 5) were prepared by melt quench technique. XRD pattern shows that there is no sharp peak it confirms the amorphous nature of the present glasses. The glass transition temperature (T{sub g}) of this glass system have been studied using the Matac MBS-8000 Digital Signal Processing and Conventional Thermal Analysis (DTA) method. The T{sub g} of these glasses increases with increase in concentration of Pr{sub 6}O{sub 11} except at 0.2 mol%, T{sub g} value is lower. {sup 11}B MAS-NMR shows the presence of sharp peak around 0.306 ppm. Chemical shift of these glasses decreases with mol% of rare earth oxide. FTIR spectra recorded in the region of 400 to 4000 cm{sup -1}. This studies revealed that the progressive addition Ag{sub 2}O and Pr{sub 6}O{sub 11} leads to modification of B{sub 2}O{sub 3} into BO{sub 4} groups. Raman measurements of these glasses support the proposed interpretations of the experimental results.

Jagadeesha Gowda, G. V. [Dept. of Physics, Sapthagiri College of Engineering, Bangalore, Karnataka (India); Eraiah, B. [Dept.of Physics, Bangalore University, Karnataka (India)

2013-02-05

6

Synthesis and structural studies of praseodymium doped silver borate glasses  

NASA Astrophysics Data System (ADS)

Praseodymium doped silver borate glasses with nominal composition xPr6O11-(25-x)Ag2O-75B2O3 (x=0, 1, 2, 3, 4, 5) were prepared by melt quench technique. XRD pattern shows that there is no sharp peak it confirms the amorphous nature of the present glasses. The glass transition temperature (Tg) of this glass system have been studied using the Matac MBS-8000 Digital Signal Processing and Conventional Thermal Analysis (DTA) method. The Tg of these glasses increases with increase in concentration of Pr6O11 except at 0.2 mol%, Tg value is lower. 11B MAS-NMR shows the presence of sharp peak around 0.306 ppm. Chemical shift of these glasses decreases with mol% of rare earth oxide. FTIR spectra recorded in the region of 400 to 4000 cm-1. This studies revealed that the progressive addition Ag2O and Pr6O11 leads to modification of B2O3 into BO4 groups. Raman measurements of these glasses support the proposed interpretations of the experimental results.

Jagadeesha Gowda, G. V.; Eraiah, B.

2013-02-01

7

Optical properties of Dy3+ doped bismuth zinc borate glass and glass ceramics  

NASA Astrophysics Data System (ADS)

Dy3+ doped bismuth zinc borate transparent glasses were prepared by melt quenching technique and these glasses were used precursor to obtain transparent glass ceramics by heat treatment method. XRD pattern of the glass ceramic shows the formation of the ?-BiB3O6 and Bi2ZnOB2O6 phases. The visible emission intensity of the glass ceramics is stronger than the glass. This can be due to the formation of nano nonlinear optical crystallites in glass matrix.

Shanmugavelu, B.; Kanth Kumar, V. V. Ravi

2012-06-01

8

Neodymium-doped barium borate glasses as fluorescent concentrators for the infrared spectral range  

NASA Astrophysics Data System (ADS)

Neodymium-doped barium borate glasses are investigated for their potential as fluorescent concentrators for the near infrared spectral range. Additional doping of the glasses with silver oxide and subsequent heat treatment leads to a reduction of the doped silver ions and to the formation of metallic silver nanoparticles. The formation of the silver nanoparticles is indicated by a broad surface plasmon-related extinction band at approximately 410 nm. The influence of the silver nanoparticles on the fluorescence properties is investigated.

Dyrba, Marcel; Wiegand, Marie-Christin; Ahrens, Bernd; Schweizer, Stefan

2012-05-01

9

Elastic properties of Li+ doped lead zinc borate glasses  

NASA Astrophysics Data System (ADS)

Glasses in the system 0.25PbO-(0.25-x) ZnO-0.5B2O3-xLi2O have been prepared by the melt quenching technique. Elastic properties, DSC studies have been employed to study the role of Li2O in the present glass system. Elastic properties and Debye temperature have been determined using pulsed echo ultrasonic interferometer operating at 10MHz. Sound velocities Vl, Vt and elastic moduli decrease up to 5 mol% and then gradually increase with increase in Li2O concentration. Debye temperature and the glass transition temperature decreases with increase in Li2O. Densities remains almost constant up to 15 mol% Li2O concentration and increases monotonically while the molar volume decreases with the increase of Li2O concentration. The results are discussed in view of the borate structural network and dual role of Zn and Pb in these glasses.

Rajaramakrishna, R.; Lakshmikantha, R.; Anavekar, R. V.

2014-04-01

10

The dependence of luminescence on reduction of Sm2+ ions doped in lithium barium borate glasses  

NASA Astrophysics Data System (ADS)

Sm3+-doped Li2O-BaO-B2O3 glass was prepared by the conventional melt quenching method in air atmosphere. Sm2+ ions were obtained by two methods, i.e. heating the as-made glass in a reducing atmosphere and irradiating the sample under X-rays. The two obtained samples were investigated by luminescence spectra and lifetime measurements. It was found that the conversion of Sm3+?Sm2+ after X-ray irradiation is efficient in this borate glass. Photo-stability of Sm2+ ions was evaluated by the photo-bleaching method. Furthermore, thermo-luminescence was also measured. The different defects and the reduction mechanism of Sm2+ ions in this borate glass were discussed. This would be helpful to understand the reduction mechanism of Sm2+ ions in borate glasses.

Li, Yadong; Huang, Yanlin; Jiang, Chuanfang; Jang, Kiwan

2009-11-01

11

Barium borate glass and transparent glass ceramics doped with Pb4Lu2YbF17  

NASA Astrophysics Data System (ADS)

Barium borate glasses doped with complex Pb4Lu2YbF17 fluoride have been synthesized and investigated. Heat treatment produced glass ceramics containing the crystalline BaF2:Yb3+ phase. The changes in the structural and optical properties of the glass ceramics were revealed by X-ray diffraction, Raman spectroscopy, and luminescence spectroscopy of Yb3+ ions in polycrystalline Pb4Lu2YbF17, initial glass, and glass ceramics.

Petrova, O. B.; Dmitruk, L. N.; Popov, A. V.; Shukshin, V. E.

2009-09-01

12

Crystalline patterning in Sm-doped sodium borate glass by CW Nd:YAG laser irradiation  

Microsoft Academic Search

Laser irradiation of glass materials has drawn much attention because this technique can offer a new processing method for spatially selected structural modification and\\/or crystallization in glass. Crystallized line and dot patterns at the micrometer scale were fabricated on the surface of Sm-doped sodium borate (Na2O–B2O3) glass by irradiation of a continuous-wave Nd:YAG laser at ?=1064nm. The pattern sizes could

Yusok Lim; Myeongkyu Lee

2007-01-01

13

NIR Luminescence From Nd3+ And Er3+ Ions Doped Cadmium Borate Glasses For Optical Amplification  

NASA Astrophysics Data System (ADS)

In this paper, we report the near-infrared luminescence from the Nd3+ and Er3+ ions doped cadmium borate glasses for optical amplification. The absorption and luminescence spectra of the host glass matrix have been carried out at room temperature. From these spectra, Judd-Ofelt intensity and laser parameters have been computed and discussed. The NIR spectra of Nd3+ and Er3+ ions doped glasses have shown full-width at half maxim (FWHW) around 19, 21, 22 and 24 nm respectively. These glasses have potential applications in broadly tunable laser sources and broadband optical amplification at low-loss telecommunication windows.

Sharm, Y. K.; Joshi, R. P.; Surana, S. S. L.

2011-12-01

14

Structural and optical properties of niobium doped silver-lead-borate glasses  

NASA Astrophysics Data System (ADS)

Nb2O5 doped silver lead borate glasses with the chemical composition (29--x)PbO-1Ag2O-70B2O3-xNb2O5 (where x=0.1mol % and 0.5 mol %) have prepared by conventional melt quenching method. FTIR and UV absorption technique have been used in order to obtain the information concerning network structure. As Nb2O5 concentration increased, the borate glass network is shown to change three coordinated to four coordinated boron system. SEM technique confines glassy nature of the prepared samples. The calculated optical band gap increases with increase Nb2O5 concentration.

Sathish, M.; Eraiah, B.

2013-06-01

15

Optical properties of alkali and alkaline-earth lead borate glasses doped with Nd 3+ Ions  

Microsoft Academic Search

Spectroscopic and physical properties of Nd3+-doped alkali lead borate glasses of type 20R\\u000a 2O · 30PbO · 49.5B2O3 · 0.5Nd2O3 (R = Li and K) and alkaline-earth lead borate glasses 20RO · 30PbO · 49.5B2O3 · 0.5Nd2O3 (R = Ca, Ba, and Pb) have been investigated. Optical absorption spectra have been used to determine the Slater-Condon (F2, F4, and F6),

S. Mohan; K. S. Thind; D. Singh; L. Gerward

2008-01-01

16

Luminescence properties of Ce 3+ and Tb 3+ doped rare earth borate glasses  

Microsoft Academic Search

Ce3+- and Tb3+-doped rare earth borate glasses were synthesized and their luminescence properties have been studied. The sample containing Ce3+ ions has a strong purplish-blue emission and that doped with Tb3+ emits a green light under UV excitation. The Ce3+ ions in the host form two kinds of emission centers, owing to different lattice sites occupied by Ce3+ in the

Lihui Huang; Xiaojun Wang; Hai Lin; Xingren Liu

2001-01-01

17

Infrared broadband emission of bismuth-doped barium-aluminum-borate glasses  

Microsoft Academic Search

We report near infrared broadband emission of bismuth-doped barium-aluminum-borate glasses. The broadband emission covers 1.3µm window in optical telecommunication systems. And it possesses wide full width at half maximum (FWHM) of ~200nm and long lifetime as long as 350µs. The luminescent properties are quite sensitive to glass compositions and excitation wavelengths. Based on energy matching conditions, we suggest that the

Xian-Geng Meng; Jian-Rong Qiu; Ming-Ying Peng; Dan-Ping Chen; Quan-Zhong Zhao; Xiong-Wei Jiang; Cong-Shan Zhu

2005-01-01

18

Optical absorption and photoluminescence in Sm 3+- and Eu 3+-doped rare-earth borate glasses  

Microsoft Academic Search

Sm3+- and Eu3+-doped rare-earth borate glasses (Li2O–BaO–La2O3–B2O3) have been fabricated and characterized optically. The density, refractive index, optical absorption, Judd-Ofelt parameters, and spontaneous transition probabilities have been measured, calculated and analyzed. Sm3+ and Eu3+ emit intense reddish-orange and red lights under blue and UV light excitations, respectively. In Sm3+ and Eu3+ co-doped glasses, the excitation wavelength range of Eu3+ emission

Hai Lin; Dianlai Yang; Guishan Liu; Tiecheng Ma; Bin Zhai; Qingda An; Jiayou Yu; Xiaojun Wang; Xingren Liu; Edwin Yue-Bun Pun

2005-01-01

19

Optical properties and spectroscopic parameters of Nd 3+-doped phosphate and borate glasses  

Microsoft Academic Search

Neodymium doped borate and phosphate glass specimens have been prepared by the melt quenching technique. Their absorption spectra have been recorded in the region 300–1000 nm. The Judd–Ofelt theory has been applied to the measured values of absorption line strengths to evaluate the spontaneous emission probabilities from the 4F3\\/2 level, quantum efficiencies and stimulated emission cross sections of the 4F3\\/2?4I11\\/2

V. Mehta; G Aka; A. L Dawar; A Mansingh

1999-01-01

20

Structural studies of lead lithium borate glasses doped with silver oxide.  

PubMed

Silver oxide doped lead lithium borate (LLB) glasses have been prepared and characterized. Structural and composition characterization were accessed by XRD, FTIR, Raman, SEM and EDS. Results from FTIR and Raman spectra indicate that Ag(2)O acts as a network modifier even at small quantities by converting three coordinated to four coordinated boron atoms. Other physical properties, such as density, molar volume and optical basicity are also evaluated. Furthermore, they are also affected by the silver oxide composition. PMID:22088558

Coelho, João; Freire, Cristina; Hussain, N Sooraj

2012-02-01

21

Preparation and properties of silver-borate glasses doped with praseodymium oxide  

NASA Astrophysics Data System (ADS)

Silver-borate glasses doped with Praseodymium oxide having composition xPr6O11-(25-x)Ag2O-75B2O3 (x = 0,1,2,3,4,5mol%) were prepared by conventional melt quenching method. The density, molar volume, and optical energy band gap of these glasses have been measured. Optical absorption spectra of these glasses were recorded in the range 300-1000 nm at room temperature. The optical energy band gap obtained in the present work is 1.9531eV to 2.4166 eV.

Gowda, G. V. Jagadeesha; Eraiah, B.

2013-06-01

22

Optical absorption and photoluminescence properties of Er3+ doped mixed alkali borate glasses.  

PubMed

An investigations of the optical absorption and fluorescence spectra of 0.2 mol% Er2O3 in mixed alkali borate glasses of the type 67.8B2O3 x xLi2O(32-x)Na2O, 67.8B2O3 x xLi2O(32-x)K2O and 67.8B2O3 x xNa2O(32-x)K2O (where x = 8, 12, 16, 20 and 24) are presented. The glasses were obtained by quenching melts consisting of H3BO3, Li2CO3, Na2CO3, K2CO3 and Er2O3 (950-1100 degrees C, 1.5-2 h) between two brass plates. Spectroscopic parameters like Racah (E1, E2 and E3), spin-orbit (xi(4f)) and configuration interaction (alpha) parameters are deduced as function of x. Using Judd-Ofelt theory, Judd-Ofelt intensity parameters (omega2, omega4 and omega6) are obtained. Radiative and non-radiative transition rates (A(T) and W(MPR)), radiative lifetimes (tauR), branching ratios (beta) and integrated absorption cross-sections (sigma) have been computed for certain excited states of Er3+ in these mixed alkali borate glasses. Emission spectra have been studied for all the three Er3+ doped mixed alkali borate glasses. The present paper throws light on the trends observed in the intensity parameters, radiative lifetimes, branching ratios and emission cross-sections as a function of x in these borate glasses, keeping in view the effect of mixed alkalies in borate glasses. PMID:15911407

Ratnakaram, Y C; Kumar, A Vijaya; Naidu, D Tirupathi; Rao, J L

2005-07-01

23

Infrared broadband emission of bismuth-doped barium-aluminum-borate glasses  

NASA Astrophysics Data System (ADS)

We report near infrared broadband emission of bismuth-doped barium-aluminum-borate glasses. The broadband emission covers 1.3µm window in optical telecommunication systems. And it possesses wide full width at half maximum (FWHM) of ~200nm and long lifetime as long as 350µs. The luminescent properties are quite sensitive to glass compositions and excitation wavelengths. Based on energy matching conditions, we suggest that the infrared emission may be ascribed to 3P1?¨ 3P0 transition of Bi+. The broad infrared emission characteristics of this material indicate that it might be a promising candidate for broadband optical fiber amplifiers and tunable lasers.

Meng, Xian-Geng; Qiu, Jian-Rong; Peng, Ming-Ying; Chen, Dan-Ping; Zhao, Quan-Zhong; Jiang, Xiong-Wei; Zhu, Cong-Shan

2005-03-01

24

Spectroscopic investigations on Pr3+ and Nd3+ doped strontium-lithium-bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Spectroscopic investigations on different concentrations (0.1, 0.5, 1.0, 1.5 and 2.0 mol%) of Pr3+ and Nd3+ doped strontium lithium bismuth borate glasses have been done. X-ray diffraction, SEM with EDS, absorption and luminescence spectra were recorded for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images conformed amorphous nature of investigated glass samples. EDS spectra of host glass and Pr3+doped glass matrices gave information about the chemical composition of glass samples. From the absorption spectra of Pr3+ and Nd3+ ions, Judd-Ofelt (J-O) intensity parameters (??,? = 2, 4 and 6) have been calculated and compared with other glass matrices. The emission characteristics such as radiative lifetimes (?R), measured and calculated branching ratios (?) and stimulated emission cross-sections (?P) have been obtained for the observed emission transitions of Pr3+ and Nd3+ ions in the above glass matrix for all the concentrations. From the emission spectra of Pr3+ and Nd3+ doped glass matrices, the effect of concentration on the quenching of intensity of 1D2 ? 3H4 transition of Pr3+ ion and 4F3/2 ? 4I9/2, 4I11/2 and 4I13/2 transitions of Nd3+ have been studied and discussed.

Rajesh, D.; Balakrishna, A.; Seshadri, M.; Ratnakaram, Y. C.

2012-11-01

25

Physical, structural, and luminescence studies of Nd3+ doped MgO-ZnO borate glass  

NASA Astrophysics Data System (ADS)

A series of borate glass of the system xNd2O3-5MgO-20ZnO-(75 - x)B2O3, where x = 0.5, 1.0,1.5, 2.0, and 2.5 was successfully fabricated using melt quench method. The properties of the glass were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), absorption and luminescence spectra. The upconversion properties of Nd3+ doped borate glass were observed by using 574 nm excitation wavelength corresponding to 4 I 15/2 ? 2 H 114/2 transition. The emission bands centered at 460, 500 and 620 nm which corresponding to the Nd3+ transitions, 4 F 7/2 ? 4 I 15/2, 2 H 11/2 ? 4 I 15/2, and 4 F 9/2 ? 4 I 15/2 respectively were observed at room temperature. The presence of Nd3+ in borate based glass could intensify the upconversion luminescence spectra as it can potentially be used as host materials for upconversion lasers.

Razali, W. A. W.; Azman, K.; Hashim, S.; Alajerami, Yasser Saleh Mustafa; Syamsyir, S. A.; Mardhiah, A.; Ridzwan, M. H. J.

2013-11-01

26

Structural, dielectric and AC conductivity properties of Co2+ doped mixed alkali zinc borate glasses  

NASA Astrophysics Data System (ADS)

The Co2+ doped 19.9ZnO+5Li2CO3+25Na2CO3+50B2O3 (ZLNB) mixed alkali zinc borate glasses have been prepared by a conventional melt quenching method. The structural (XRD & FT-IR), dielectric and a.c. conductivity (?ac) properties have been investigated. Amorphous nature of these glasses has been confirmed from their XRD pattern. The dielectric properties and electrical conductivity (?ac) of these glasses have been studied from 100Hz to 5MHz at the room temperature. Based on the observed trends in the a.c. conductivities, the present glass samples are found to exhibit a non-Debye behavior.

Madhu, B. J.; Banu, Syed Asma; Harshitha, G. A.; Shilpa, T. M.; Shruthi, B.

2013-02-01

27

Gamma-ray interaction with copper-doped bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Ultraviolet (UV)-visible, infrared (IR) and Raman spectroscoies together with thermal properties of Bi 2O 3-B 2O 3-CuO glasses were measured before and after gamma irradiation. It was shown that the UV-visible spectrum of the undoped Cu-free glass reveals before irradiation intense charge transfer UV bands due to the interference of trace iron impurities and Bi 3+ while the visible spectrum shows no absorption bands. The CuO-doped glass reveals a broad visible band characteristic for Cu 2+ ions. The absorption spectra of all the glasses show resistance to successive gamma irradiation. This shielding behavior is related to the high atomic mass of the metal ions (Bi 3+). IR and Raman measurements reveal absorption bands which are characteristic for various groups of borate network and [BiO 6] octahedra.

ElBatal, F. H.; Marzouk, S. Y.; Nada, N.; Desouky, S. M.

2007-03-01

28

Optical Properties of Alkaline Earth Ions Doped Bismuth Borate Glasses  

NASA Astrophysics Data System (ADS)

The optical properties of glasses with composition xLi2O (30-x) Bi2O3-70B2O3 x = 0, 5, 10, 15 & 20 mol %, prepared by normal melt quench technique were investigated by means of UV-VIS measurement. It was observed that the optical band gap of the present glass system decreases with increasing Li2O content up to 15 mol%, and with further increase in lithium oxide content i.e. x>15 mol% the optical band gap increases. It was also observed that the present glass system behaves as an indirect band gap semiconductor.

Kundu, Virender; Dhiman, R. L.; Maan, A. S.; Goyal, D. R.

2011-07-01

29

Elastic properties of silver borate glasses doped with praseodymium oxide  

NASA Astrophysics Data System (ADS)

A series of glasses xPr6O11-(35-x) Ag2O-65B2O3 with x=0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol % were synthesized by melt quenching technique. Longitudinal and shear ultrasonic velocity were measured at 5 MHz frequency and at room temperature. Elastic moduli, Poisson's ratio and Debye temperature have been calculated from the measured density and ultrasonic velocity at room temperature. The experimental results indicate that the elastic constants depend upon the composition of the glasses. The role of the Pr6O11 inside the glass network was discussed.

Gowda, G. V. Jagadeesha; Eraiah, B.

2014-04-01

30

Three-dimensional optical memory using photoluminescence change in Sm-doped sodium borate glass  

SciTech Connect

The feasibility of three-dimensional (3D) optical memory has been demonstrated by utilizing the photoluminescence (PL) spectrum change in a Sm-doped fluoride glass [K. Miura, J. Qiu, S. Fujiwara, S. Sakasuchi, and K. Hirao, Appl. Phys. Lett. 80 2263 (2002)]. We here report on a femtosecond laser-induced PL change in a Sm-doped sodium borate glass that is easier to synthesize and its potential application to 3D memory. Irradiation with a femtosecond pulsed laser (800 nm, 1 kHz, 100 fs) induced a PL peak near 682 nm, resulting from the photoreduction of the Sm ions. A multilayer pattern (bit size=1 {mu}m,layer separation=8 {mu}m) formed by femtosecond laser irradiation was read out by a reflection-type fluorescent confocal microscope, which detected the emission at 682 nm as a signal. High-contrast pattern images were obtained without crosstalk.

Lim, Jinhyong; Lee, Myeongkyu; Kim, Eunkyoung [Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Department of Chemical Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

2005-05-09

31

Spectroscopic features of manganese doped tellurite borate glass ceramics  

NASA Astrophysics Data System (ADS)

Glass system of composition (50-x)TeO2-5Sb2O3-45B2O3: xMnO with ‘x’ ranging from 0.3 to 1.5 mol% has been prepared via melt quenching followed by controlled crystallization. Further, the samples were characterized by X-ray diffraction, scanning electron microscopy and DSC techniques. A number of studies viz., optical absorption, EPR, and luminescence of these glass ceramics have been carried out. The spectroscopic studies have confirmed the existence of manganese ions in trivalent state in addition to divalent. EPR spectra of all investigated glass ceramics exhibit resonance signals that are characteristic for Mn2+ ions. The changes found in all the properties as function of the crystallizing agent (MnO) have been discussed in detail.

Satyanarayana, T.; Valente, M. A.; Nagarjuna, G.; Veeraiah, N.

2013-02-01

32

Optical studies of Sm3+ ions doped Zinc Alumino Bismuth Borate glasses  

NASA Astrophysics Data System (ADS)

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of samarium (Sm3+) ions were prepared by using melt quenching technique and characterized for their lasing potentialities in visible region by using the techniques such as optical absorption, emission and emission decay measurements. Radiative properties for various fluorescent levels of Sm3+ ions were estimated from absorption spectral information using Judd-Ofelt (JO) analysis. The emission spectra and con-focal photoluminescence images obtained by 410 nm laser excitation demonstrates very distinct and intense orange-red emission for all the doped glasses. The suitable concentration of Sm3+ ions in these glasses to act as an efficient lasing material has been discussed by measuring the emission cross-section and branching ratios for the emission transitions. The quantum efficiencies were also been estimated from emission decay measurements recorded for the 4G5/2 level of Sm3+ ions. From the measured emission cross-sections, branching ratios, strong photoluminescence features and CIE chromaticity coordinates, it was found that 1 mol% of Sm3+ ions doped ZnAlBiB glasses are most suitable for the development of visible orange-red lasers.

Swapna, K.; Mahamuda, Sk.; Srinivasa Rao, A.; Shakya, S.; Sasikala, T.; Haranath, D.; Vijaya Prakash, G.

33

Optical Absorption, ESR and Termoluminescence (TL) in Copper-Doped Lithium Borate Glasses.  

National Technical Information Service (NTIS)

Boron oxide plays a significant role in numerous glasses of high technological importance, such as nuclear wastes management, electronics, low density fibrous silica insulation used in space vehicles, and radiation dosimetry. Lithium borate glasses were p...

E. F. Chinaglia M. L. F. Nascimento M. Matsuoka S. Watanabe

1999-01-01

34

The Preparation and Characterization of Nd{sub 2}O{sub 3} Doped Borate Glass  

SciTech Connect

The Nd{sup 3+} doped borate glass of Nd{sub 2}O{sub 3}-MgO-ZnO-B{sub 2}O{sub 3} glass system is successfully been prepared by melt-quenched technique. Batches of 15g were prepared from certified reagent grades of B{sub 2}O{sub 3}(99.95% purity), MgO (97%), ZnO (98% purity), and Nd{sub 2}O{sub 3}(99.99%). The measured glass densities are found varies from 5683.2 kgm{sup -3} to 5724.0 kgm{sup -3}. The increment in density implies that an addition of Nd{sub 2}O{sub 3} with higher atomic masses than B{sub 2}O{sub 3} tend to increase the packing density of the glass structures since the atomic masses of B{sub 2}O{sub 3} and Nd{sub 2}O{sub 3} are 69.62 and 336.42 respectively. From the density values obtained, the molar volume of glasses was calculated. From the results, it is found that the molar volume of these glasses decreases slightly from 22.50 cm{sup 3} to 27.54 cm{sup 3} with respect to Nd{sub 2}O{sub 3} content.

Razali, Wan Aizuddin Wan; Kasim, Azman; Mohamed, Ruziana [Optical Material Group, Universiti Teknologi MARA Pahang, Bandar Jengka, Pahang (Malaysia)

2010-07-07

35

Effect of co-doped SnO2 nanoparticles on photoluminescence of cu-doped potassium lithium borate glass  

NASA Astrophysics Data System (ADS)

The SnO2 co-doped lithium potassium borate glasses doped with 0.05, 0.10, 0.25 and 0.50 mol% of Cu were synthesized by the melt quenching technique. The SnO2 co-dope was added to the compounds in the amounts of 0.05, 0.10, and 0.20 mol%. The photoluminescent spectrum for different concentrations of copper was studied. It was observed that the intensity of blue emission (450, 490 nm) varies with concentration mol%. In addition, with different concentration of SnO2 to 0.10 mol% Cu, the influence of the luminescence has been observed to enhance intensity and shifted to blue and red (490, 535 nm) emissions.

Namma, Haydar Aboud; Wagiran, H.; Hussin, R.; Ariwahjoedi, B.

2012-09-01

36

Thermoluminescence properties of the Cu-doped lithium potassium borate glass.  

PubMed

Characteristics of lithium potassium borate glasses with various copper concentrations are reported. The glasses were prepared by the melt quenching method and irradiated with photons to doses in the 0.5-4.0Gy range. Glowing curves, dose response curves, reproducibility of the response, dose threshold, thermal fading and optical bleaching were studied. PMID:24681645

Aboud, Haydar; Wagiran, H; Hussin, R; Ali, Hassan; Alajerami, Yasser; Saeed, M A

2014-08-01

37

Effect of 3d-transition metal doping on the shielding behavior of barium borate glasses: A spectroscopic study.  

PubMed

UV-visible and FT infrared spectra were measured for prepared samples before and after gamma irradiation. Base undoped barium borate glass of the basic composition (BaO 40%-B2O3 60mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe(3+)) within the chemical raw materials. 3d transition metal (TM)-doped glasses exhibit extra characteristic absorption bands due to each TM in its specific valence or coordinate state. The optical spectra show that TM ions favor generally the presence in the high valence or tetrahedral coordination state in barium borate host glass. Infrared absorption bands of all prepared glasses reveal the appearance of both triangular BO3 units and tetrahedral BO4 units within their characteristic vibrational modes and the TM-ions cause minor effects because of the low doping level introduced (0.2%). Gamma irradiation of the undoped barium borate glass increases the intensity of the UV absorption together with the generation of an induced broad visible band at about 580nm. These changes are correlated with suggested photochemical reactions of trace iron impurities together with the generation of positive hole center (BHC or OHC) within the visible region through generated electrons and positive holes during the irradiation process. PMID:24983922

ElBatal, H A; Abdelghany, A M; Ghoneim, N A; ElBatal, F H

2014-12-10

38

Broad-spectrum antibacterial properties of metal-ion doped borate bioactive glasses for clinical applications  

NASA Astrophysics Data System (ADS)

Bioactive glasses with antimicrobial properties can be implemented as coatings on medical devices and implants, as well as a treatment for tissue repair and prevention of common hospital-acquired infections such as MRSA. A borate-containing glass, B3, is also undergoing clinical trials to assess wound-healing properties. The sensitivities of various bacteria to B3, B3-Ag, B3-Ga, and B3-I bioactive glasses were tested. In addition, the mechanism of action for the glasses was studied by spectroscopic enzyme kinetics experiments, Live-Dead staining fluorescence microscopy, and luminescence assays using two gene fusion strains of Escherichia coli. It was found that gram-positive bacteria were more sensitive to all four glasses than gram negative bacteria, and that a single mechanism of action for the glasses is unlikely, as the rates of catalysis for metabolic enzymes as well as membrane permeability were altered after glass exposure.

Ottomeyer, Megan

39

Spectroscopic studies of lead antimony borate glasses doped with erbium ions  

NASA Astrophysics Data System (ADS)

Antimony borate glasses of the composition 30PbO-25Sb2O3-(45-x)B2O3-xEr2O3 with x = 0 to 1.0 in steps of 0.2 were prepared by the melt-quenching method. Various physical parameters. radiative parameters, transition probability A, branching ratio ? and the radiative life time ? for different emission levels of Er3+ ions, have been evaluated.

Reddy, M. Chandra Shekhar; Goud, K. Krishna Murthy; Dharmaiah, P.; Rao, B. Appa

2013-06-01

40

Development of biomimetic coatings on Sm oxide doped ELB (Eu–Li–borate) glasses  

Microsoft Academic Search

The in-vitro biomineralization of Eu\\/Li–borate glasses containing Sm2O3 was investigated by immersion in simulated body fluid (SBF) up to 72h. Back scattering scanning electron microscope supplemented with EDX was used to follow the development of the phosphatic layer post 72h SBF immersion. Biochemical analyses of calcium and inorganic phosphorus (Ca2+ and iP) ions were conducted using relevant biochemical kits and

M. A. K. Elfayoumi; Wafa I. Abdel-Fattah; Gehan T. El-Bassyouni

2010-01-01

41

The structural, optical and magnetic parameter of manganese doped strontium zinc borate glasses  

NASA Astrophysics Data System (ADS)

Glasses with composition 10SrO:(30-x)ZnO:60B2O3:xMnO, 0?x?0.9 (all compositions in wt%) have been prepared and investigated by X-ray diffraction, EPR, Optical absorption and FT-IR spectroscopic techniques. The XRD pattern of all the glasses confirmed the formation of an amorphous structure. The EPR spectra of all glass samples exhibit resonance signals at g?2.0 with a sextet of hyperfine lines. The spin concentration (N) and temperature dependence of EPR signals were studied for Mn2+ ions in strontium zinc borate glass samples. The zero-field splitting parameter D has been evaluated from the intensities of the allowed hyperfine lines. The paramagnetic susceptibility (?) was calculated from EPR data at different temperatures and the Curie temperature (?p) was calculated from the 1/? verses T graph. The optical absorption spectra exhibit a single broad band near 470 nm and this has been attributed to the spin-allowed 5Eg?5T2g transition of Mn3+ ions in octahedral symmetry. The theoretical optical basicity (?th) of these glasses have also been evaluated. The FTIR studies show BO3 and BO4 structural units in strontium zinc borate glasses.

Sumalatha, B.; Omkaram, I.; Rajavardhana Rao, T.; Linga Raju, Ch.

2013-02-01

42

Optical and photophysical investigation of Meso, Proto and Hematoporphyrin(IX)dimethylester doped hybrid borate glasses  

NASA Astrophysics Data System (ADS)

Hybrid borate glasses containing different concentrations (0.5-2.0 mg in 12 g of boric acid) of Mesoporphyrin(IX)dimethylester, Protoporphyrin(IX)dimethylester and Hematoporphyrin(IX)dimethylester were prepared by rapid melt quench technique at 230 °C. The hybrid glass samples were characterized by X-ray diffraction, optical absorption, steady state and time-resolved fluorescence emission. The optical absorption spectrum shows red-shift in Soret band along with change in Q-band pattern. The intensity of Q-band was found to increase with increase in the concentration of porphyrin in the glass. Steady state emission spectrum shows strong S 2?S 0 emission in the range 462-495 nm and blue shift in S 1?S 0 emission. Time-resolved fluorescence emission and fluorescence excitation spectra showed that different structures of porphyrins were exist in the glass samples. The variation in the spectral behaviour in the glass was correlated with those in solution medium and possible structures of porphyrin in borate glass were explored.

Venkatramaiah, N.; Soorya, V. C.; Venkatesan, R.

2011-02-01

43

Thermoluminescence dosimetry properties and kinetic parameters of lithium potassium borate glass co-doped with titanium and magnesium oxides.  

PubMed

Lithium potassium borate (LKB) glasses co-doped with TiO2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of (60)Co to study their thermoluminescence (TL) properties. The TL glow curve of the Ti-doped material featured a single prominent peak at 230°C. Additional incorporation of MgO as a co-activator enhanced the TL intensity threefold. LKB:Ti,Mg is a low-Z material (Zeff=8.89) with slow signal fading. Its radiation sensitivity is 12 times lower that the sensitivity of TLD-100. The dose response is linear at doses up to 10(3) Gy. The trap parameters, such as the kinetics order, activation energy, and frequency factor, which are related to the glow peak, were determined using TolAnal software. PMID:24929526

Hashim, S; Alajerami, Y S M; Ramli, A T; Ghoshal, S K; Saleh, M A; Abdul Kadir, A B; Saripan, M I; Alzimami, K; Bradley, D A; Mhareb, M H A

2014-09-01

44

Precipitation of ZnO in Al 2O 3-doped zinc borate glass ceramics  

NASA Astrophysics Data System (ADS)

Crystallization behavior of the oxide semiconductor ZnO in zinc borate glass was investigated. The precipitated crystalline phase of glass ceramics containing a small amount of Al 2O 3 was ?-Zn 3B 2O 6 whereas that of the glass ceramics containing a large amount of Al 2O 3 was ZnO. It was found that the c-oriented precipitation of ZnO in a glass ceramic was brought about by the in-plane crystal growth of needle-like ZnO crystallites along the a-axis. Amount of Al 2O 3 that can make glass network affected the coordination state of B 2O 3 in the glass, and a three-coordinated BO 3 unit was preferentially formed in the glass containing a higher amount of Al 2O 3. The present results suggest that crystallization of ZnO from multi-component glass is dominated by the local coordination state of the mother glass.

Masai, Hirokazu; Ueno, Takahiro; Takahashi, Yoshihiro; Fujiwara, Takumi

2011-10-01

45

Photon Interaction Parameters for Some Borate Glasses  

NASA Astrophysics Data System (ADS)

Some photon interaction parameters of dosimetric interest such as mass attenuation coefficients, effective atomic number, electron density and KERMA relative to air have been computed in the wide energy range from 1 keV to 100 GeV for some borate glasses viz. barium-lead borate, bismuth-borate, calcium-strontium borate, lead borate and zinc-borate glass. It has been observed that lead borate glass and barium-lead borate glass have maximum values of mass attenuation coefficient, effective atomic number and KERMA relative to air. Hence, these borate glasses are suitable as gamma ray shielding material, packing of radioactive sources etc.

Mann, Nisha; Kaur, Updesh; Singh, Tejbir; Sharma, J. K.; Singh, Parjit S.

2010-11-01

46

Photon Interaction Parameters for Some Borate Glasses  

SciTech Connect

Some photon interaction parameters of dosimetric interest such as mass attenuation coefficients, effective atomic number, electron density and KERMA relative to air have been computed in the wide energy range from 1 keV to 100 GeV for some borate glasses viz. barium-lead borate, bismuth-borate, calcium-strontium borate, lead borate and zinc-borate glass. It has been observed that lead borate glass and barium-lead borate glass have maximum values of mass attenuation coefficient, effective atomic number and KERMA relative to air. Hence, these borate glasses are suitable as gamma ray shielding material, packing of radioactive sources etc.

Mann, Nisha [Department of Applied Sciences, Samalkha Group of Institutions, Samalkha-132 101, Haryana (India); Kaur, Updesh; Singh, Tejbir; Sharma, J. K. [Department of Physics, Maharishi Markandeshwar University, Mullana-133 207, Haryana (India); Singh, Parjit S. [Department of Physics, Punjabi University, Patiala-147 002, Punjab (India)

2010-11-06

47

Borate Glasses, Crystals and Melts.  

National Technical Information Service (NTIS)

The Final Proceedings for Borate, Glasses, Crystals and Melts, 22 July 1996 - 25 July 1996. This is an interdisciplinary conference. Topics include glass forming systems, triborate systems, structural studies, modeling and computer simulation, super-ionic...

1997-01-01

48

Gradient index in borate glasses  

NASA Astrophysics Data System (ADS)

A number of aluminum-borate glasses has been developed for producing gradient index glasses by exchanging. Both positive and negative axial gradient were fabricated in the glasses by exchange of Li+ for Na+ and Na+ for Li+, respectively. Index change to 0.03 and gradient index Abble number larger than +100 were achieved. The diffusion coefficients of Na+ and Li+ in borate glasses were calculated by fitting the profiles of refractive index to complimentary error function.

Sun, Yunan; Kindred, Douglas S.; Moore, Duncan T.

1994-08-01

49

Optical absorption and photoluminescence properties of Dy3+ doped heavy metal borate glasses - Effect of modifier oxides  

NASA Astrophysics Data System (ADS)

The present paper aims at reporting the optical absorption and emission properties of Dy3+ doped alkali (Li, Na, K) and mixed alkali (Li-Na, Li-K, Na-K) heavy metal borate glasses. For these glasses X-ray diffraction (XRD), differential scanning calorimetry (DSC), optical absorption, emission and lifetime decay measurements were carried out. Glass transition temperatures are obtained from the DSC spectra. Judd-Ofelt theory has been used to derive the spectral intensities (f), Judd-Ofelt intensity parameters (?2, ?4 and ?6) and certain radiative properties. Using the Judd-Ofelt intensity parameters, radiative lifetimes (?R), branching ratios (?), integrated absorption cross-sections (?) and emission cross-sections (?P) were obtained. The variations in these parameters with the variation of glass matrix are discussed in detail. The decay lifetime of the 4F9/2 level has been measured from the decay profiles and compared with calculated lifetimes. From the emission spectra, chromacity color coordinates are calculated and indicated the white light emission for potassium glass matrices. It was observed that among various glass matrices, potassium glass matrix has exhibited large emission cross-section for 6F9/2 ? 6H13/2 transition.

Sasi kumar, M. V.; Rajesh, D.; Balakrishna, A.; Ratnakaram, Y. C.

2013-06-01

50

Electrical, dielectric and optical properties of La2O3 doped lithium borate glasses  

NASA Astrophysics Data System (ADS)

Effect of La2O3 addition on electrical and optical properties of lithium borate glass has been studied in the present work. Glass system with general formula 27.5 Li2O-(72.5-X) B2O3-X La2O3 was prepared by normal melting process. Electrical properties were studied by impedance spectroscopy. Scaling behavior was introduced to study dynamical process. In order to study optical properties, absorption spectra were measured at room temperature. Direct and indirect optical band gap, Urbach energy and Fermi energy were calculated from absorption spectra using functionality of extinction coefficient from Fermi-Dirac distribution function. Optical parameter shows the dependence on physical properties i.e. density and molar volume. There is good correlation between electrical and optical properties.

Gedam, R. S.; Ramteke, D. D.

2013-07-01

51

Track characteristics and detection in borate glasses doped with fissionable material  

NASA Astrophysics Data System (ADS)

Fission fragment tracks were registered on the surface of alumino-borate glass using natural uranium foil as external radiator followed by chemical etching in hydrofluoric acid. In another glasses, of the same base composition to which uranium atoms (as internal radiators) were added, neutrons were applied directly on its surface and the tracks were detected. The track densities in both cases were found to be a function of neutron doses. However, in the former case, the relative volume of the track was found to increase with increasing etching time, while that of the second case seems to increase an the initial stages of etching and then hardly changes in a certain region, after which it increases again. The relative volume of the tracks in the second case is smaller when compared with that in the former case, however, application of gamma radiation seems to increase again the relative track volume. The results are discussed on the basis of structural changes that may occur during the interaction of neutron and gamma radiation with glass.

Morsi, Morsi M.; El-Konsol, Salah; Adawi, Mohamed A.

1983-12-01

52

Intense visible fluorescence and energy transfer in Dy 3+, Tb 3+, Sm 3+ and Eu 3+ doped rare-earth borate glasses  

Microsoft Academic Search

Tb3+\\/Dy3+ and Eu3+\\/Sm3+ doped rare-earth borate glasses have been synthesized and characterized. Under UV excitation, Dy3+, Tb3+, Sm3+ and Eu3+ emit intense yellowish white, green, reddish orange and red lights, respectively. In Tb3+\\/Dy3+ co-doped glasses, the enhancement of Tb3+ green emission is observed, and the sensitization is related to the efficient energy transfer from Dy3+ to Tb3+. In Eu3+\\/Sm3+ co-doped

Hai Lin; Edwin Yue-Bun Pun; Xiaojun Wang; Xingren Liu

2005-01-01

53

Electron paramagnetic resonance of vanadyl doped mixed alkaline earth borate glasses  

NASA Astrophysics Data System (ADS)

The ``mixed alkaline effect'' is one of the classical anomalies of glass science. We report here an interesting phenomenon ``Mixed Alkaline earth oxide Effect'' observed in a series of VO2+ ions doped in xMgO-(30-x)BaO-68B2O3-2V2O5 glass system. Glasses are investigated by EPR technique at X-band frequencies. The EPR spectra of all the glasses exhibited resonance signals characteristic of VO2+ ions in octahedral coordination with tetragonal compression and have C4V symmetry with ground state dxy. Tetragonality (?gll/?g?) of V4+ ion sites exhibited non-linear variation with MgO content, which indicated change in the ligand field at the site of V4+.

Samdani; Chandrasekhar, K.; Shareefuddin, Md.; Chary, M. Narasimha

2013-06-01

54

Thermo-optical characteristics and concentration quenching effects in Nd3+ doped yttrium calcium borate glasses.  

PubMed

In this work we present a comprehensive study of the spectroscopic and thermo-optical properties of a set of samples with composition xNd(2)O(3)-(5-x)Y(2)O(3-)40CaO-55B(2)O(3) (0 ? x ? 1.0 mol%). Their fluorescence quantum efficiency (?) values were determined using the thermal lens technique and the dependence on the ionic concentration was analyzed in terms of energy transfer processes, based on the Förster-Dexter model of multipolar ion-ion interactions. A maximum ? = 0.54 was found to be substantially higher than for yttrium aluminoborate crystals and glasses with comparable Nd(3+) content. As for the thermo-optical properties of yttrium calcium borate, they are comparable to other well-known laser glasses. The obtained energy transfer microparameters and the weak dependence of ? on the Nd(3+) concentration with a high optimum Nd(3+) concentration put this system as a strong candidate for photonics applications. PMID:21456672

Santos, D R S; Santos, C N; de Camargo, A S S; Silva, W F; Santos, W Q; Vermelho, M V D; Astrath, N G C; Malacarne, L C; Li, M S; Hernandes, A C; Ibanez, A; Jacinto, C

2011-03-28

55

Formation and evolution of magnetic nanoparticles in borate glass simultaneously doped with Fe and Mn oxides  

Microsoft Academic Search

Evolution of the phase state of paramagnetic additions at various stages of synthesis and subsequent thermal treatment of glasses of the system Al2O3-K2O-B2O3 simultaneously doped with Fe2O3 and MnO is studied by means of a combination of experimental techniques: Faraday rotation (FR), electron magnetic resonance (EMR), transmission electron microscopy (TEM), Mössbauer spectroscopy, and magnetic measurements. Both FR and EMR show

J. Kliava; I. Edelman; O. Ivanova; R. Ivantsov; O. Bayukov; E. Petrakovskaja; V. Zaikovskiy; I. Bruckental; Y. Yeshurun; S. Stepanov

2008-01-01

56

Luminescence property of rare-earth-doped bismuth-borate glasses with different concentrations of bismuth and rare-earth material  

NASA Astrophysics Data System (ADS)

Bismuth-borate glass scintillators have high density and good radiation hardness. Thus, if they are highly luminescent, they can be applied in astrophysics, high-energy and nuclear physics, homeland security, radiation detection and medical imaging. Bismuth-borate glasseswith the formula xBi2O3:(100 - x)B2O3 ( x = 30, 50, and 66.7 mol%) were fabricated and doped with Nd, Er, Dy, Pr, Sm, Ho, Gd, and Ce in different dopant concentrations by using the melt-quenching technique. The X-ray emission spectra for the bismuth-borate glasses were measured and showed that only Sm-, Dy-, and Nd-doped glass scintillators had noticeable luminescence. Also, we measured the photo-luminescence and the proton-induced emission spectra. We obtained the result that Sm- and Dy- doped glass scintillators emitted luminescence. The emission peaks of the Sm- doped glass were 569, 598, 641, and 708 nm and were due to (4G5/2 ? 6H J ) ( J = 5/2, 7/2, 9/2, 11/2) transitions, respectively. The emission peaks of the Dy- doped glass were at 485 nm (4F9/2 ? 6H15/2), 575 nm (4F9/2 ? 6H13/2), 660 nm (4F9/2 ? 6H11/2), and 755 nm (4F9/2 ? 6H9/2 + 6H11/2), and that of the Nd-doped glass was at 895 nm due to the (4F3/2 ? 4I9/2) transition. The luminescence intensities were compared in terms of different Bi concentrations and dopant concentrations.

Park, J. M.; Kim, H. J.; Limsuwan, P.; Kaewkhao, J.

2012-07-01

57

Thermal and optical properties of Nd3+ doped lead zinc borate glasses—Influence of alkali metal ions  

NASA Astrophysics Data System (ADS)

In the present investigation a new series of six different Nd3+ doped alkali and mixed alkali (Li, Na, K, Li-Na, Li-K and Na-K) heavy metal (PbO and ZnO) borate glasses were prepared using the melt quenching technique. The amorphous nature of the glass systems has been identified based on the X-ray diffraction analysis. The glass transition studies were carried out using differential scanning calorimetry (DSC). Optical properties were studied by measuring the optical absorption and near infrared luminescence spectra. The Judd-Ofelt (J-O) theory has been applied to calculate J-O intensity parameters, ?? (?=2, 4 and 6) and in turn used to estimate radiative properties of certain transitions. Spectroscopic parameters such as transition probabilities (AT), branching ratios (?), radiative lifetimes (?R) and integrated absorption cross-sections (?) were calculated using J-O intensity parameters for all transitions. Using emission spectra, experimental branching ratios and stimulated emission cross-sections (?P) are obtained for all the observed emission transitions.

Sasi Kumar, M. V.; Rajesh, D.; Balakrishna, A.; Ratnakaram, Y. C.

2013-04-01

58

Structural investigation and electron paramagnetic resonance of vanadyl doped alkali niobium borate glasses  

NASA Astrophysics Data System (ADS)

Glasses with compositions xNb 2O 5·(30 - x)M 2O·69B 2O 3 (where M = Li, Na, K; x = 0, 4, 8 mol%) doped with 1 mol% V 2O 5 have been prepared using normal melt quench technique. The IR transmission spectra of the glasses have been studied over the range 400-4000 cm -1. The changes caused by the addition of Nb 2O 5 on the structure of these glasses have been reported. The electron paramagnetic resonance spectra of VO 2+ ions in these glasses have been recorded in X-band (9.14 GHz) at room temperature (300 K). The spin Hamiltonian parameters, dipolar hyperfine coupling parameter and Fermi contact interaction parameter have been calculated. It is observed that the resultant resonance spectra contain hyperfine structures (hfs) due to V 4+ ions which exist as VO 2+ ions in octahedral coordination with a tetragonal compression in the present glasses. The tetragonality of V 4+O 6 complex decreases with increasing concentration of Nb 2O 5. The 3d xy orbit contracts with increase in Nb 2O 5:M 2O ratio. Values of the theoretical optical basicity, ? th, have also been reported.

Agarwal, A.; Sheoran, A.; Sanghi, S.; Bhatnagar, V.; Gupta, S. K.; Arora, M.

2010-03-01

59

Structural investigation and electron paramagnetic resonance of vanadyl doped alkali niobium borate glasses.  

PubMed

Glasses with compositions xNb(2)O(5).(30-x)M(2)O.69B(2)O(3) (where M=Li, Na, K; x=0, 4, 8 mol%) doped with 1 mol% V(2)O(5) have been prepared using normal melt quench technique. The IR transmission spectra of the glasses have been studied over the range 400-4000 cm(-1). The changes caused by the addition of Nb(2)O(5) on the structure of these glasses have been reported. The electron paramagnetic resonance spectra of VO(2+) ions in these glasses have been recorded in X-band (9.14 GHz) at room temperature (300 K). The spin Hamiltonian parameters, dipolar hyperfine coupling parameter and Fermi contact interaction parameter have been calculated. It is observed that the resultant resonance spectra contain hyperfine structures (hfs) due to V(4+) ions which exist as VO(2+) ions in octahedral coordination with a tetragonal compression in the present glasses. The tetragonality of V(4+)O(6) complex decreases with increasing concentration of Nb(2)O(5). The 3d(xy) orbit contracts with increase in Nb(2)O(5):M(2)O ratio. Values of the theoretical optical basicity, Lambda(th), have also been reported. PMID:20060775

Agarwal, A; Sheoran, A; Sanghi, S; Bhatnagar, V; Gupta, S K; Arora, M

2010-03-01

60

The spectroscopic properties of Er 3+-doped antimony-borate glasses  

NASA Astrophysics Data System (ADS)

The spectroscopic properties of Er 3+-doped Sb 2O 3-B 2O 3 glass have been investigated for developing 1.55-?m broadband fiber amplifiers and tunable lasers. A broad 1.55-?m near infrared emission peaked at 1527 nm with a full width at half maximum (FWHM) of 91 nm has been obtained for 30Sb 2O 3-69B 2O 3-1Er 2O 2 glass upon excitation of a 980 nm laser diode. This broad luminescence locates in the region of 1440-1650 nm and covers the S, C and L bands. The emission cross-section of the 4I 13/2? 4I 15/2 transition of Er 3+ ions and the measured lifetime of the 4I 13/2 level of Er 3+ ions are 6.01×10 -21 cm 2 and 0.341 ms, respectively. Based on the electronic polarizability of the oxide ion and optical basicity estimated from the values of refractive index and molar volumes, the covalent bonding character in the local ligand environments around Er 3+ in Sb 2O 3-B 2O 3 glasses increases with increasing Sb 2O 3 content. It is noted that the product of the emission cross-section and the FWHM of the glass, ? e×FWHM, is as great as 567×10 -28 cm 3, which is comparable or higher than that of Er 3+-doped tellurite- and germanate-based glasses.

Qian, Q.; Zhang, Q. Y.; Jiang, H. F.; Yang, Z. M.; Jiang, Z. H.

2010-05-01

61

Formation and evolution of magnetic nanoparticles in borate glass simultaneously doped with Fe and Mn oxides  

NASA Astrophysics Data System (ADS)

Evolution of the phase state of paramagnetic additions at various stages of synthesis and subsequent thermal treatment of glasses of the system Al2O3-K2O-B2O3 simultaneously doped with Fe2O3 and MnO is studied by means of a combination of experimental techniques: Faraday rotation (FR), electron magnetic resonance (EMR), transmission electron microscopy (TEM), Mössbauer spectroscopy, and magnetic measurements. Both FR and EMR show that magnetically ordered clusters occur already at the first stage of the glass preparation. In particular, for the ratio of the Fe and Mn oxides in the charge close to 3:2, fine magnetic nanoparticles are formed with characteristics similar to those of manganese ferrite. By computer simulating the EMR spectra at variable temperatures, a superparamagnetic nature of these nanoparticles is confirmed and their mean diameter is estimated as approximately 3.2 nm. In the thermally treated glasses larger magnetic nanoparticles are formed, giving rise to FR spectra, characteristic of magnetically ordered systems, and the EMR spectra different from those in as-prepared glasses but also showing superparamagnetic narrowing. The Mössbauer spectroscopy corroborates the manganese ferrite structure of the nanoparticles and indicates their coexistence in the ferrimagnetic and superparamagnetic states. The TEM shows the presence of polydisperse nanoparticles on the background of the glass matrix, and electron diffraction of a selected region containing larger particles indicates a crystal structure close to that of MnFe2O4. Energy-dispersive atomic x-ray spectra confirm that the major part of Fe and Mn introduced to the glass composition is gathered in the particles, with the concentration ratio close to 2:1, characteristic of bulk MnFe2O4. Magnetic hysteresis loops of samples subjected to an additional thermal treatment demonstrate a strong increase in the coercive force, remnant magnetization, and high-field magnetic susceptibility with temperature decrease. The consistent results obtained using various techniques demonstrate that the formation of nanoparticles with characteristics close to those of MnFe2O4 confers to these glasses magnetic and magneto-optical properties typical of substances possessing magnetic order.

Kliava, J.; Edelman, I.; Ivanova, O.; Ivantsov, R.; Bayukov, O.; Petrakovskaja, E.; Zaikovskiy, V.; Bruckental, I.; Yeshurun, Y.; Stepanov, S.

2008-11-01

62

The influence of cation additives on the NIR luminescence intensity of Er3+-doped borate glasses  

NASA Astrophysics Data System (ADS)

Er3+-doped 25BaO-(25-x)SiO2-xAl2O3-25B2O3 transparent glasses are prepared with x = 0, 12.5 and 25 by a solid-state reaction. The Er-related NIR luminescence intensity, which corresponds to the transition of 4I15/2-4I13/2, is obviously altered with different silicon/aluminum ratios. The Judd-Ofelt parameters of the Er3+ ions are adopted to explain the intensity change in the NIR fluorescence, and the Raman scattering intensity versus the amount of Al and/or Si components are discussed. The spectra of the three samples are quite similar in the peak positions, but different in intensity. The maximal phonon density of state for the samples is calculated from the Raman spectra and is correlated to the NIR luminescence efficiency.

Zhou, Yong-Liang; Zhang, Xiao-Song; Xu, Jian-Ping; Zhang, Zhong-Peng; Zhang, Gao-Feng; Wei, Feng-Wei; Li, Lan

2012-06-01

63

Spectroscopy and energy transfer in lead borate glasses doubly doped with Dy(3)(+)-Tb(3+) and Tb(3)(+)-Eu(3+) ions.  

PubMed

Lead borate glasses doubly doped with Dy(3)(+)-Tb(3+) and Tb(3+)-Eu(3+) were investigated using optical spectroscopy. Luminescence spectra of rare earths were detected under various excitation wavelengths. The main green emission band due to (5)D4?(7)F5 transition of Tb(3+) is observed under excitation of Dy(3+), whereas the main red emission band related to (5)D0?(7)F2 transition of Eu(3+) is successfully observed under direct excitation of Tb(3+). In both cases, the energy transfer processes from Dy(3+) to Tb(3+) and from Tb(3+) to Eu(3+) in lead borate glasses occur through a nonradiative processes with efficiencies up to 16% and 18%, respectively. The presence of energy transfer process was also confirmed by excitation spectra measurements. PMID:24824577

Pisarska, Joanna; Kos, Agnieszka; Pisarski, Wojciech A

2014-08-14

64

Structural investigations of some bismuth–borate–vanadate glasses doped with gadolinium ions  

Microsoft Academic Search

X-ray diffraction (XRD), Fourier transform infrared (FTIR) and electron paramagnetic resonance (EPR) spectroscopies have been\\u000a employed to investigate the xGd2O3 · (95 ? x)[2Bi2O3 · B2O3] · 5V2O5 glass system, with 0 ? x ? 25 mol%. The glass samples have been prepared by melting at 1,100 °C for 10 min followed by rapid cooling at room temperature.\\u000a The structure of samples was analyzed by means of XRD. The pattern obtained did not reveal any

Petru Pascuta

2010-01-01

65

Optical characterization of Mn 2+, Ni 2+ and Co 2+ ions doped zinc lead borate glasses  

Microsoft Academic Search

This paper reports on the development and optical characterization of heavy metal oxide (HMO)-based transparent glasses in the chemical composition of 15PbO–40B2O3–(45?x) ZnO?x TM2+ (=Mn2+ or Ni2+ or Co2+) (where x=0.2, 0.5mol%). For these glasses both absorption and emission spectra have been measured, in order to understand their optical performances. The XRD profiles have confirmed their glassy nature and the

A. Thulasiramudu; S. Buddhudu

2006-01-01

66

Structure and properties of rare earth-doped lead borate glasses  

Microsoft Academic Search

Influence of rare earth oxide (Nd2O3, Er2O3) addition on structure and glass properties has been investigated in PbO–B2O3–Al2O3–WO3 system. With an increasing of rare earth concentration, intensity of OH band drastically decreases and IR transparency is slightly shifted to the longer wavelengths. The ErBO3 crystalline phase has been identified basing on X-ray diffraction analysis. In opposite to the neodymium oxide,

W. A. Pisarski; T. Goryczka; B. Wodecka-Du?; M. P?o?ska; J. Pisarska

2005-01-01

67

Structural and physical properties of vanadium doped copper bismuth borate glasses  

NASA Astrophysics Data System (ADS)

The structural and physical properties of xCuO(30-x)Bi2O3-70B2O3 x = 0, 5, 10, 15, 20 & 25 mol % with 2 mol % V2O5 glasses prepared by normal melt quench technique have been investigated by means of FT-IR & physical measurement techniques. With the addition of copper oxide (x <= 10 mol%), the frequency bands in the higher region shift towards lower wave number, suggest the conversion of BO3 to BO4 structural units, which in turn give rise to the formation of Non Bridging Oxygen's (NBOs). For further increase in CuO (i.e. for x >= 10 mol %), the frequency bands shift towards higher wave number, indicate the formation of Bridging Oxygen's (BOs). The FTIR analysis reveals that the present glass system is based on the BiO3 pyramidal, BiO6 octahedral units and also on BO3 and BO4 structural units. The systematic variation in density and molar volume in these glasses indicates the effect of CuO substitution.

Dhiman, R. L.; Kundu, Virender Singh; Arora, Susheel; Maan, A. S.

2013-02-01

68

Structural and physical properties of vanadium doped copper bismuth borate glasses  

SciTech Connect

The structural and physical properties of xCuO(30-x)Bi{sub 2}O{sub 3}-70B{sub 2}O{sub 3}; x= 0, 5, 10, 15, 20 and 25 mol % with 2 mol %V{sub 2}O{sub 5} glasses prepared by normal melt quench technique have been investigated by means of FT-IR and physical measurement techniques. With the addition of copper oxide (x{<=} 10 mol%), the frequency bands in the higher region shift towards lower wave number, suggest the conversion of BO{sub 3} to BO{sub 4} structural units, which in turn give rise to the formation of Non Bridging Oxygen's (NBOs). For further increase in CuO (i.e. for x{>=} 10 mol %), the frequency bands shift towards higher wave number, indicate the formation of Bridging Oxygen's (BOs). The FTIR analysis reveals that the present glass system is based on the BiO{sub 3} pyramidal, BiO{sub 6} octahedral units and also on BO{sub 3} and BO{sub 4} structural units. The systematic variation in density and molar volume in these glasses indicates the effect of CuO substitution.

Dhiman, R. L. [P. G. Department of Applied Physics, S. D. College, Ambala Cantt.-133 001 (India); Kundu, Virender Singh [Department of Electronic Science, Kurukshetra University, Kurukshetra-136 119 (India); Arora, Susheel; Maan, A. S. [Department of Physics, Maharishi Dayanand University, Rohtak 124 001 (India)

2013-02-05

69

XRD and EPR structural investigation of some zinc borate glasses doped with iron ions  

NASA Astrophysics Data System (ADS)

Glasses in the system xFe2O3·(100-x) [45ZnO·55B2O3] (0?x?10 mol%) have been prepared by melting at 1200 °C and rapidly cooling at room temperature. The obtained samples were submitted to an additional thermal treatment at 570 °C for 12 h in order to relax the glass structure as well as to improve the local order. The as cast and heat treated samples were investigated using X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) measurements. The XRD patterns of all the studied samples show their vitreous nature. Structural modifications occurring in the heat treated samples compared to the untreated ones have been pointed out. EPR spectra of untreated and heat treated samples revealed resonance absorptions centered at g?2.0, g?4.3 and g?6.4. The compositional variation of the line intensity and linewidth of the absorptions from g?4.3 and g?2.0 have been interpreted in terms of the variation in the concentration of the Fe3+ ions and the interaction between the iron ions. The EPR spectra of the untreated samples containing 5 mol% Fe2O3 have been studied at different temperatures (110-290 K). The line intensity of the resonance signals decreases with increase in temperature whereas the linewidth is found to be independent of temperature. It was also found that the temperature variation of reciprocal line intensity obeys the Boltzmann law.

Stefan, Razvan; Pascuta, Petru; Popa, Adriana; Raita, Oana; Indrea, Emil; Culea, Eugen

2012-02-01

70

Cooperative luminescence sensitisation and spontaneous Raman scattering in a borate glass doped with Pr{sup 3+} and Nd{sup 3+} ions  

SciTech Connect

Cooperative sensitisation of luminescence of Nd{sup 3+} ions at the {sup 4}F{sub 3/2} {yields} {sup 4}I{sub 13/2}, {sup 4}I{sub 9/2} transitions by Pr{sup 3+} ions was observed in a borate glass doped with Pr{sup 3+}-Nd{sup 3+} ion pairs. The luminescence was excited by a 800-mW, 1.064-{mu}m Nd{sup 3+}:YAG laser. Simultaneously, spontaneous Raman scattering was observed in glasses containing Pr{sup 3+}-Nd{sup 3+} ion pairs or only Pr{sup 3+} ions. The Stokes shift from the 9398-cm{sup -1} excitation line is 794 cm{sup -1}. The mechanism of nonradiative energy transfer is discussed. (laser applications and other topics in quantum electronics)

Chanturiya, G F; Kutaladze, L M; Tatarashvili, R A [Institute of Cybernetics of the Academy of Sciences of Georgia, Tbilisi (Georgia); Shchegolikhin, Aleksandr N [Institute for Biochemical Physics, Russian Academy of Sciences, Moscow (Russian Federation)

2004-04-30

71

Regulation of structure rigidity for improvement of the thermal stability of near-infrared luminescence in Bi-doped borate glasses.  

PubMed

The effect of heat-treatment on the near-infrared (NIR) luminescence properties was studied in Bi-doped borate glasses. The luminescence intensity generally decreases with the increase of temperature, and the thermal stability can be improved by nearly 4.5 times with addition of 5 mol% La2O3. Collaborative studies by using steady photoluminescence (PL) and photoluminescence excitation (PLE) spectra, luminescence decay curve, differential thermal analysis (DTA), Raman spectra and X-ray diffraction (XRD) indicate that the luminescence decrement is associated with the agglomeration of Bi active centers during heat-treatment. The improvement of the thermal stability of NIR luminescence with the addition of La2O3 is benefited from the enhancement of structure rigidity due to the strong cationic field strength of La3+. The results not only provide valuable guidance for suppressing performance degradation of Bi-doped glass during fiber drawing process, but also present an effective way to control the luminescence properties of main group elements in glasses from the perspective of glass structure. PMID:24514300

Guo, Qiangbing; Xu, Beibei; Tan, Dezhi; Wang, Juechen; Zheng, Shuhong; Jiang, Wei; Qiu, Jianrong; Zhou, Shifeng

2013-11-18

72

Characterization of Cr3+ doped mixed alkali ions effect in zinc borate glasses - Physical and spectroscopic investigations  

NASA Astrophysics Data System (ADS)

The physical and structural properties of Cr3+ doped 19.9 ZnO + xLi2O + (30 - x) Na2O + 50B2O3 (5 ? x ? 25) (ZLNB) glasses have been studied. Powder X-ray diffraction patterns indicated the amorphous nature of the glass samples. The physical parameters of all the glasses were also evaluated with respect to the composition. They exhibit the non-linearity providing the evidence for mixed alkali ions effect. The infrared spectra of the glasses in the range 400-4000 cm-1 showed the presence of BO3 and BO4 local structures in all the glass systems. No boroxol ring formation was observed in the structure of these glasses. Optical absorption and electron paramagnetic resonance studies were carried out at room temperature. From the optical absorption data various optical parameters such as optical band gap, Urbach energy were evaluated. Crystal field and Racah parameters are evaluated from optical absorption spectra. The EPR spectra of Cr3+ doped ZLNB glasses exhibited resonance signals at g = 4.066 and g = 1.9779 characteristic of Cr3+ ions. The evaluated bonding parameters suggest the covalent nature.

Rama Sundari, G.; Pushpa Manjari, V.; Raghavendra Rao, T.; Satish, D. V.; Rama Krishna, Ch.; Venkata Reddy, Ch.; Ravikumar, R. V. S. S. N.

2014-06-01

73

Electron paramagnetic resonance, optical transmission spectra and DC conductivity studies of vanadyl-doped alkali halide borate glasses  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance, optical transmission spectra and DC conductivity of the glasses 2 xMX·(0.30- x) M2O ·0.70B 2O 3 ( M=Na or K; X=Cl or Br) (0.01? x?0.10) containing 2.0 mol% of V 2O 5 have been studied. The spin-Hamiltonian parameters (SHP) of the VO 2+ ions, the dipolar hyperfine parameter, P, the Fermi contact interaction parameter, K, and the molecular orbital coefficients ( ?2 and ?2) have been calculated. It is observed that in K X·K 2O ·B 2O 3 ( X=Cl or Br) glasses, the tetragonal nature of V 4+O 6 complex decreases with KBr for x?0.05. An increase in the 2K X:K 2O ratio ( x?0.05) also results in the contraction of 3dxy orbit of the unpaired electron in the vanadyl ion, whereas in case of Na X·Na 2O ·B 2O 3 ( X=Cl or Br) glasses, the SHP are independent of change in 2Na X: M2O ratio. It is observed that the SHP in these alkali halide borate glasses are independent of the theoretical optical basicity, ?th. It is also observed that the DC conductivity increases with increase in temperature. The order of conductivity is 10 -6 ? -1 m -1 at low temperatures and 10 -4 ? -1 m -1 at high temperatures. In MCl ·M2O ·B 2O 3 ( M=Na or K) glasses, the conductivity increases and the activation energy decreases with an increase in mol% of the NaCl or KCl content whereas, in MBr ·M2O ·B 2O 3 ( M=Na or K) glasses, the conductivity first increases and then decreases with mol% of the MBr content.

Khasa, S.; Seth, V. P.; Gahlot, P. S.; Agarwal, A.; Krishna, R. M.; Gupta, S. K.

2003-07-01

74

Superparamagnetic resonance of ferric ions in devitrified borate glass  

Microsoft Academic Search

Drastic changes are observed in magnetic resonance spectra of borate glasses doped with low concentrations of iron oxide, after heat treatment above the glass transition temperature. A sharp gef = 4.3 line, characteristic of diluted Fe3+ ions in the vitreous matrix, progressively disappears in the course of treatment. A new two-line pattern grows in the vicinity of gef ? 2.0,

René Berger; Jean-Claude Bissey; Janis Kliava; Benoît Soulard

1997-01-01

75

Interfacial reactions between titanium and borate glass.  

National Technical Information Service (NTIS)

Interfacial reactions between melts of several borate glasses and titanium have been investigated by analytical scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). A thin titanium boride interfacial layer is detected by XPS afte...

R. K. Brow S. K. Saha J. I. Goldstein

1992-01-01

76

Effect of Li 2O content on physical and structural properties of vanadyl doped alkali zinc borate glasses  

NASA Astrophysics Data System (ADS)

The effect of Li 2O content in vanadyl doped 20ZnO+ xLi 2O+(30- x)Na 2O+50B 2O 3 (5? x?25) glasses has been studied with respect to their physical and structural properties. The absence of sharp peaks in XRD spectra of these glass samples confirms the amorphous nature. The physical parameters like density, refractive index, ionic concentration and electronic polarizability vary non-linearly with x mol% depending on the diffusivities of alkali ions. EPR and optical absorption spectra reveal that the resonance signals are characteristics of VO 2+ ions in tetragonally compressed octahedral site. Spin-Hamiltonian, crystal field, tetragonal field and bonding parameters are found to be in good agreement with the other reported glass systems. The tetragonal distortion ( g?- g?) and Dt reveals that their values vary non-linearly with Li 2O content and reaches a minimum at x=10 mol%. An anomaly of character has been observed in all the properties of vanadyl doped glass systems, which gives a clear indication of mixed alkali effect.

Raghavendra Rao, T.; Rama Krishna, Ch.; Udayachandran Thampy, U. S.; Venkata Reddy, Ch.; Reddy, Y. P.; Sambasiva Rao, P.; Ravikumar, R. V. S. S. N.

2011-05-01

77

Bioactive borate glass coatings for titanium alloys.  

PubMed

Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na(2)O-CaO-B(2)O(3) system, modified by additions of SiO(2), Al(2)O(3), and P(2)O(5), were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid for 2 weeks at 37 degrees C; similar layers form on 45S5 Bioglass((R)) exposed to the same conditions. Assays with MC3T3-E1 pre-osteoblastic cells show the borate glasses exhibit in vitro biocompatibility similar to that of the 45S5 Bioglass((R)). An enameling technique was developed to form adherent borate glass coatings on Ti6Al4V alloy, with adhesive strengths of 36 +/- 2 MPa on polished substrates. The results show these new borate glasses to be promising candidates for forming bioactive coatings on titanium substrates. PMID:18415004

Peddi, Laxmikanth; Brow, Richard K; Brown, Roger F

2008-09-01

78

Bioactive borate glass coatings for titanium alloys  

Microsoft Academic Search

Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na2O–CaO–B2O3 system, modified by additions of SiO2, Al2O3, and P2O5, were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction\\u000a analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid

Laxmikanth Peddi; Richard K. Brow; Roger F. Brown

2008-01-01

79

Er{sup 3+}-doped strontium lithium bismuth borate glasses for broadband 1.5 {mu}m emission - optical properties  

SciTech Connect

Strontium lithium bismuth borate glasses (SLBiB) doped with various concentrations of Er{sup 3+} were prepared using conventional melt quench technique and investigated their optical properties. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. Optical properties were studied by measuring the optical absorption and near infrared luminescence spectra at room temperature. Judd-Ofelt (J-O) theory has been applied for the f.f transitions of Er{sup 3+} ions to evaluate J-O intensity parameters, {Omega}{lambda} ({lambda} = 2, 4 and 6). Using the J-O intensity parameters, radiative properties such as transition probabilities (A{sub R}), branching ratios ({beta}) and radiative lifetimes ({tau}) are estimated for certain transitions. From the emission spectra, peak emission-cross sections ({sigma}{sub p}) and products of stimulated emission cross-section and full width at half maximum ({sigma}{sub p} Multiplication-Sign FWHM) were calculated for the observed emission transition, {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2}.

Rajesh, D.; Balakrishna, A.; Ratnakaram, Y. C. [Department of Physics, Sri Venkateswara University, Tirupati-517502 (India)

2013-02-05

80

Comparative study of ion conducting pathways in borate glasses  

SciTech Connect

The conduction pathways in metal-halide doped silver, lithium, and sodium diborate glasses have been examined by bond valence analysis of reverse Monte Carlo (RMC) produced structural models of the glasses. Although all glass compositions have basically the same short-range structure of the boron-oxygen network, it is evident that the intermediate-range structure is strongly dependent on the type of mobile ion. The topography of the pathways and the coordination of the pathway sites differ distinctly between the three glass systems. The mobile silver ions in the AgI-doped glass tend to be mainly iodine-coordinated and travel in homogeneously distributed pathways located in salt-rich channels of the borate network. In the NaCl-doped glass, there is an inhomogeneous spatial distribution of pathways that reflects the inhomogeneous introduction of salt ions into the glass. However, since the salt clusters are not connected, no long-range conduction pathways are formed without including also oxygen-rich regions. The pathways in the LiCl-doped glass are slightly more evenly distributed compared to the NaCl-doped glass (but not as ordered as in the AgI-doped glass), and the regions of mainly oxygen-coordinated pathway sites are of higher importance for the long-range migration. In order to more accurately investigate how these differences in the intermediate-range order of the glasses affect the ionic conductivity, we have compared the realistic structure models to more or less randomized structures. An important conclusion from this comparison is that we find no evidence that a pronounced intermediate-range order in the atomic structure or in the network of conduction pathways, as in the AgI-doped glass, is beneficial for the dc conductivity.

Hall, Andreas; Swenson, Jan [Department of Applied Physics, Chalmers University of Technology, S-412 96 Goeteborg (Sweden); Adams, Stefan [Department of Materials Science and Engineering, National University of Singapore, 117576 (Singapore)

2006-11-01

81

Effect of WO 3 on the spectroscopic properties in Er 3+/Yb 3+ co-doped bismuth-borate glasses  

NASA Astrophysics Data System (ADS)

The spectroscopic properties of Er 3+/Yb 3+ co-doped Bi 2O 3-B 2O 3-WO 3 (BBW) glasses were analyzed and discussed. The effect of WO 3 content on the absorption spectra, the Judd-Ofelt parameters ? t ( t=2, 4, 6), emission spectra and the lifetime of the 4I 13/2 level and the quantum efficiency of Er 3+: 4I 13/2? 4I 15/2 transition were also investigated. With the substitution of WO 3 for B 2O 3, the measured lifetime of the 4I 13/2 level and the quantum efficiency of Er 3+: 4I 13/2? 4I 15/2 transition increase from 0.98 to 1.31 ms and from 38.2% to 49.2%, respectively. The effective width of emission band and the emission cross-section both decrease slightly. And the emission spectra is analyzed via the different curve ( ?e- ?a) of BBW glasses, the influence of OH - is also discussed.

Wang, Jun; Zhou, Yaxun; Dai, Shixun; Xu, Tiefeng; Nie, Qiuhua

2007-11-01

82

The local structure of bismuth borate glasses doped with europium ions evidenced by FT-IR spectroscopy  

Microsoft Academic Search

Glasses of the xEu2O3 · (100 ? x)[4Bi2O3 · B2O3] system, with 0 ? x ? 40 mol% were studied by FT-IR spectroscopy and density measurements. FT-IR spectroscopy and density data suggest that the\\u000a europium ions play the network modifier role in the studied glasses. These data show that the glass structure consists on\\u000a the BiO3, BiO6, BO3 and BO4 units, and the conversion among these units mainly depends on the

Petru Pascuta; Lidia Pop; Simona Rada; Maria Bosca; Eugen Culea

2008-01-01

83

The leaching behavior of borate waste glass SL1  

Microsoft Academic Search

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak.

Jiawei Sheng; Shanggeng Luo; Baolong Tang

1999-01-01

84

Vibrational spectra and the structure of alkali borate glasses  

SciTech Connect

This paper presents systematic data on the IR-absorption spectra of lithium borate glasses. Lithium borate glasses were synthesized from Li/sub 2/CO/sub 3/ and H/sub 3/BO/sub 3/ in Pt crucibles at temperatures from 800 to 1050 C. It was possible in the lithium borate system to obtain glasses continuing significantly more M/sub 2/O than the glasses in the sodium or potassium borate system. An analysis of the data on Raman spectra of alkali borate glasses suggests that the addition of M/sub 2/O to a B/sub 2/O/sub 3/ glass produces network disorder, the replacement of the boroxyl rings by rings of another configuration and the formation of BO/sub 4/ tetrahedra.

Kolesova, V.A.

1986-11-01

85

The effect of Ce3+ ions on the spectral and decay characteristics of luminescence phosphate-borate glasses doped with rare-earth ions  

NASA Astrophysics Data System (ADS)

The luminescent characteristics of Li2O-B2O3-P2O5-CaF2 (LBPC) glasses doped with Gd3+ and Tb3+ ions and codoped with Ce3+ are studied by pulsed optical spectrometry under electron beam excitation. It is found that in glass with Ce3+ and Gd3+ ions a decrease in the decay time of gadolinium luminescence in the 312-nm band (6 P J ? 8 S 7/2) was observed. It is shown that in the glass LBPC: Tb, Ce, an increase in the emission intensity in the main radiative transitions in terbium ion was observed. In the kinetics of luminescence band 545 nm of LBPC: Tb, Ce glasses, is present stage of buildup, the character of which changes with the doped of Ce3+ ions. The mechanism of energy transfer in LBP glasses doped with rare elements is discussed.

Valiev, D. T.; Polisadova, E. F.; Belikov, K. N.; Egorova, N. L.

2014-05-01

86

Glass Formation and Elastic Behavior of Bismuth Borate Glass System  

NASA Astrophysics Data System (ADS)

Bismuth borate glass is of great interest in optoelectronic devices due to its low melting temperature (600-800 °C), extensive glass formation range, high refractive index ranging from 1.9 to 2.3, high physical and chemical stability, and nonlinear optical property. A systematic bismuth borate glass series in the systems of (Bi2O3)x-(B2O3)1-x have been successfully prepared by melt quenching technique over a wide range of composition (x = 35-70 mol%). Their elastic properties have been measured from their densities as well as longitudinal (VL) and shear ultrasonic wave velocities (Vs) which have been determined at room temperature by the MBS8000 Ultrasonic Data Acquisition system at a frequency of 5 MHz. The variation of ultrasonic wave velocities and elastic modulus such as longitudinal, Young's, bulk and shear modulus, Poisson's ratio, and micro hardness are discussed with respect of the Bi2O3 content.

Sidek, H. A. A.; Senin, H. B.; Halimah, M. K.; Daud, W. M.; Khamirul, A. M.; Halim, A. S.

2008-05-01

87

Dielectrics of lead zirconate bonded with barium borate glass  

Microsoft Academic Search

Dielectric constant variation with temperature and frequency is reported for barium-borate glass-bonded lead zirconate. Lowering\\u000a of the relative permittivity of the ceramic is attributed to the presence of the glass.

K Singh; Aruna Indurkar

1988-01-01

88

Modifier role of cerium in lithium aluminium borate glasses  

NASA Astrophysics Data System (ADS)

Lithium aluminium borate glasses doped with CeO2 at the expense of Al2O3 have been prepared by melt quench technique. An intense fluorescence has been recorded when excited at 350 nm giving a large Stoke's shift. This emission has been attributed to 5d ? 4f transitions of Ce3+. An increase in fluorescence intensity, shifting of UV absorption edge towards longer wavelength and a decrease in band gap with addition of CeO2 concentration has been observed. Moreover densification and stabilization of glass network has been observed which is due to conversion of BO3 units to BO4 units since CeO2 at low concentrations act as a network modifier.

Kaur, Parvinder; Singh, Gurinder Pal; Kaur, Simranpreet; Singh, D. P.

2012-08-01

89

Compositional dependence of absorption spectra of Ti[sup 3+] in silicate, borate, and phosphate glasses  

SciTech Connect

Absorption spectra of Ti[sup 3+] were measured for silicate, borate, and phosphate glasses doped with 0.5 mol% Ti[sub 2]O[sub 3]. The absorption coefficient at the peak wavelength of the [sup 2]T[sub 2] [yields] [sup 2]E transition of Ti[sup 3+] is used as a parameter showing the relative content of Ti[sup 3+] ions in glass samples. The effect of glass composition on Ti[sup 3+]/Ti[sup 4+] redox was studied. For multicomponent glasses, a basicity parameter calculated from glass composition is proposed in terms of coulomb force between the cation and the oxygen ion. The value of the absorption coefficient depends on basicity in silicate and borate glasses; however, it is independent of composition in phosphate glasses.

Morinaga, K.; Yoshida, Hideki; Takebe, Hiromichi (Kyushu Univ., Fukuoka (Japan). Dept. of Materials Science and Technology)

1994-12-01

90

Acoustical investigations of borate glasses containing oxides of some transition elements and ferric oxide dopants  

NASA Astrophysics Data System (ADS)

Glass samples of manganese oxide borate and zinc oxide borate (with and without ferric oxide doping) have been prepared to study their acoustical, mechanical, and thermal behavior as function of composition. Sound velocities and attenuation measurements in these glass systems at 1,2, and 5 MHz give elastic moduli, Poissons ratio, micro-hardness, acoustic impedance, internal friction, thermal expansion coefficient and Debye and softening temperatures. Structural changes involve boron anomaly, field strengths of cations, difference in ionic radii, and charge state of iron. Makishima-Mackenzie (theoretical model) and IR and NGR techniques confirm the conclusions arrived at. The network modifier (NWM) is varied from 25 to 45 mol% for manganese oxide borate and from 15 to 40 mol% with 10 mol% doping of ferric oxide. For zinc oxide borate glasses, it varies from 26 to 34 mol% and with 10 mol% of ferric oxide, its variation is from 15 to 35 mol%. Impact of doping by ferric oxide on the properties of these glass systems have been investigated.

Bhatti, Surjit Singh; Singh, Kanwar Jit

2003-04-01

91

Bioactive borate glass scaffold for bone tissue engineering  

Microsoft Academic Search

Borate glass particles and microspheres with size distributions in the range of approximately 100–400?m, were loosely compacted and sintered for 10min at 600°C to form a porous, three-dimensional construct (porosity 25–40%). Conversion of the borate glass to hydroxyapatite was investigated by soaking the constructs in a solution of K2HPO4 (0.25M) at 37°C and with a pH value of 9.0, and

Wen Liang; Mohamed N. Rahaman; Delbert E. Day; Nicholas W. Marion; Gwendolen C. Riley; Jeremy J. Mao

2008-01-01

92

Synthesis and characterization of rare-earth doped SrBi{sub 2}Nb{sub 2}O{sub 9} phase in lithium borate based nanocrystallized glasses  

SciTech Connect

Glass composites comprising of un-doped and samarium-doped SrBi{sub 2}Nb{sub 2}O{sub 9} nanocrystallites are fabricated in the glass system 16.66SrO-16.66[(1-x)Bi{sub 2}O{sub 3}-xSm{sub 2}O{sub 3}]-16.66Nb{sub 2}O{sub 5}-50Li{sub 2}B{sub 4}O{sub 7} (0<=x<=0.5, in mol%) via the melt quenching technique. The glassy nature of the as-quenched samples is established by differential thermal analyses. Transmission electron microscopic studies reveal the presence of about 15 nm sized spherical crystallites of the fluorite-like SrBi{sub 1.9}Sm{sub 0.1}Nb{sub 2}O{sub 9} phase in the samples heat treated at 530 deg. C. The formation of layered perovskite-type un-doped and samarium-doped SrBi{sub 2}Nb{sub 2}O{sub 9} nanocrystallites with an orthorhombic structure through the intermediate fluorite phase is confirmed by X-ray powder diffraction and micro-Raman spectroscopic studies. The influence of samarium doping on the lattice parameters, lattice distortions, and the Raman peak positions of SrBi{sub 2}Nb{sub 2}O{sub 9} perovskite phase is clarified. The dielectric constants of the perovskite SrBi{sub 2}Nb{sub 2}O{sub 9} and SrBi{sub 1.9}Sm{sub 0.1}Nb{sub 2}O{sub 9} nanocrystals are relatively larger than those of the corresponding fluorite-like phase and the precursor glass. - Graphical Abstract: This figure shows the XRD patterns at room temperature for the as-quenched and heat treated samples in Sm{sub 2}O{sub 3}-doped (x=0.1) glass. Based on these results, it is concluded that the formation of samarium-doped perovskite SBN phase takes place via an intermediate fluorite-like phase in the crystallization of this glass.

Harihara Venkataraman, B. [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan); Fujiwara, Takumi [Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Komatsu, Takayuki, E-mail: komatsu@mst.nagaokaut.ac.j [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan)

2009-06-15

93

THERMAL ANALYSIS OF LEAD BORATE GLASSES DURING CRYSTALLIZATION  

Microsoft Academic Search

The crystallization behavior of 2 lead borate glasses was studied by the ; differential thermal analysis (DTA) method, and the thermal effects were ; interpreted with the aid of supplementary information obtained from measurements ; of viscosity, thermal expansion, and microstructure. The glasses were found to ; nucleate readily at the air-glass interface; thus a powdered (--60 +100-mesh) ; sample

C. G. Bergeron; C. K. Russell; A. L. Friedberg

1963-01-01

94

Interpretation of the IR spectra of alkali borate glasses  

SciTech Connect

This paper describes methods of interpretation of the IR spectra of alkali borate glasses. In view of the difficulties which are encountered in a strict interpretation of the IR spectra of crystalline oxygen-containing compounds with complex anions, semiempirical methods of interpretation are commonly used. The existence of glasses of groups with an atomic (ionic) arrangement close to that in the crystalline compounds makes it possible to a certain extent to use the spectra of crystalline compounds in the interpretation of the IR spectra of glasses. The alkali borate glass systems were chosen for this study because the information on their structure is the most detailed by comparison with other borate glasses. IR spectrospcopy showed that the spectral regions in which fundamental asymmetrical stretching vibrations in BO/sub 3/ and BO/sub 4/ polyhedra occur, in most cases, are fairly clearly defined independently of the combined or separate presence of these polyhedra. It is proposed that the bands in the IR spectra of sodium and lithium borate glasses be assigned to vibrations mostly localized on specific fragments of polyborate groups present in the glasses. The data from IR spectroscopy confirms that tetraborate groups are present in lithium borate glasses.

Chekhovskii, V.G.

1985-11-01

95

Coordination and valence state of transition metal ions in alkali-borate glasses  

NASA Astrophysics Data System (ADS)

Borate glasses of the 20R 2O·80B 2O 3 type, where R = Li, Na and K, were colored by doping with transition metal ions (Co, Ni, Cr and Mn). The glasses were obtained by melting at the temperature of 1150 °C. For these glasses optical absorption in UV-VIS-NIR range were recorded. Analysis of the spectra allows to be determined the coordination and oxidation states of the doping transition metal ions. Changes of their coordination or oxidation are presented as a function of the optical basicity ? after Duffy. Cobalt and nickel are present in examined borate glasses as divalent ions (Co 2+, Ni 2+) in octahedral coordination mainly, but the tetrahedral coordination state of cobalt is also possible. Chromium and manganese are present in the borate glasses in various oxidation state, though Cr 3+ and Mn 3+ ions in the octahedral coordination are probably dominant. A decrease of the electronegativity of the modifiers (Li ? Na ? K) and an increase of the glass matrix basicity cause a shift of the oxidation/reduction equilibrium towards higher valences of the transition metals (Cr 6+, Mn 3+).

Terczy?ska-Madej, A.; Cholewa-Kowalska, K.; ??czka, M.

2011-10-01

96

Relationship between Eu3+ reduction and glass polymeric structure in Al2O3-modified borate glasses under air atmosphere  

NASA Astrophysics Data System (ADS)

The reduction of Eu3+ to Eu2+ is realized efficiently in Eu2O3-doped borate glasses prepared under air condition by melting-quenching method. Luminescent spectra show an increasing tendency of Eu2+ emission with increasing Al2O3 concentration in B2O3-Na2O glasses. It is interesting that significant enhancement appeared of Eu2+ luminescence in the Al2O3-rich sample comparing to the samples of Al2O3 less than 6 mol%. FTIR and Raman scattering measurements indicated that some new vibration modes assigned to the low-polymerized structure groups decomposed from the slight Al2O3 dopant samples. These results demonstrated that the polymerization of the glass structure decreased with increasing incorporation of Al2O3 into the borate glasses, linking to the efficiency of Eu3+ self-reduction in air at high temperature.

Jiao, Qing; Yu, Xue; Xu, Xuhui; Zhou, Dacheng; Qiu, Jianbei

2013-06-01

97

Thickness dependent ion conductivity of lithium borate network glasses  

NASA Astrophysics Data System (ADS)

Lithium borate network glasses are possible candidates for separator membranes in all-solid-state batteries. Thin films of a Li2O-borate glass were produced by argon beam sputtering and their specific ionic conductivities were measured by impedance spectroscopy. The conductivity of as-sputtered films is about two orders of magnitude higher compared to the conductivity of bulk glasses produced from the melt. Furthermore, thin films with a thickness of 7-125 nm reveal a remarkable finite size effect after annealing: with decreasing thickness the specific dc conductivity increases about three orders of magnitude.

Berkemeier, F.; Shoar Abouzari, M.; Schmitz, G.

2007-03-01

98

Color Centers in Alkali Silicate and Borate Glasses  

Microsoft Academic Search

The color centers induced by x-ray irradiation in the alkali silicate and borate glasses and the mixed alkali glasses are studied. By preparing samples of various compositions in the reducing and in the oxidizing condition, and by optical and thermal bleaching, it is concluded that the visible band is due to electrons trapped by oxygen vacancies neighboring alkali ions and

Ryosuke Yokota

1954-01-01

99

Spectroscopic properties of Yb 3+ in bismuth borate glasses  

Microsoft Academic Search

Absorption spectra, fluorescence spectra and fluorescence decay curves have been measured at room temperature. Spectroscopic and laser performance parameters of Yb3+ in bismuth borate glasses with different compositions and Yb3+ concentrations were calculated. The effects of the host glasses compositions and Yb3+ concentration on the spectroscopic and laser performance parameters have been analyzed. The effect of radiation trapping on the

Yujin Chen; Yidong Huang; Zundu Luo

2003-01-01

100

Formation and control of Au and Ag nanoparticles inside borate glasses using femtosecond laser and heat treatment  

NASA Astrophysics Data System (ADS)

We report the spectroscopic properties of femtosecond laser-irradiated sodium-alumino-borate glass doped with silver and gold ions. We precipitated gold and silver nanoparticles by laser irradiation and annealing at 400°C for 30 min. The irradiation and annealing treatment produced different absorption and emission characteristics in Au3+ doped and Au3+, Ag+ codoped glasses, and the possible mechanisms of the observed results are discussed. The size of the nanoparticles was estimated by TEM and absorption band analysis.

Shin, Jongho; Jang, Kyungsik; Lim, Ki-Soo; Sohn, Ik-Bu; Noh, Young-Chul; Lee, Jongmin

2008-12-01

101

Optical characterization of TCO films on borate glasses for high efficiency solar cells  

NASA Astrophysics Data System (ADS)

Two different transparent conductive oxides (TCO) were deposited by magnetron sputtering on borate glasses. The influence of sputtering conditions on optical, electrical and microstructural properties was much higher for indium tin oxide (ITO) than for aluminium-doped zinc oxide (AZO) films. Specific resistivity values obtained from simulation of the optical spectra are in good agreement with values obtained from four-point probe measurements.

Steudel, Franziska; Miclea, Paul-Tiberiu; Teuscher, Nico; Heilmann, Andreas; Schweizer, Stefan

2012-05-01

102

Low-energy vibrational dynamics of cesium borate glasses.  

PubMed

Low-temperature specific heat and inelastic light scattering experiments have been performed on a series of cesium borate glasses and on a cesium borate crystal. Raman measurements on the crystalline sample have revealed the existence of cesium rattling modes in the same frequency region where glasses exhibit the boson peak (BP). These localized modes are supposed to overlap with the BP in cesium borate glasses affecting its magnitude. Their influence on the low frequency vibrational dynamics in glassy samples has been considered, and their contribution to the specific heat has been estimated. Evidence for a relation between the changes of the BP induced by the increased amount of metallic oxide and the variations of the elastic medium has been provided. PMID:22546082

Crupi, C; D'Angelo, G; Vasi, C

2012-06-01

103

Low frequency Raman investigations of lead borate and lead alumino borate glasses  

NASA Astrophysics Data System (ADS)

Lead borate and lead alumino borate glasses in the systems xPbO·(100- x)B 2O 3 (0 ? x ? 75 mol%) and xPbO·(95- x)B 2O 3, 5Al 2O 3 (0 ? x ? 80 mol%), respectively, have been prepared and investigated by Raman spectroscopy. Using the Martin-Brenig model, structural correlation lengths were determinated from Boson peak positions of temperature reduced Raman spectra and transversal sound velocities. Vv polarized spectra contain information about the nature of the PbO component within the network.

Witke, K.; Willfahrt, M.; Hübert, Th.; Reich, P.

1995-04-01

104

Infrared and Raman spectroscopic studies on alkali borate glasses: evidence of mixed alkali effect.  

PubMed

A lithium-potassium-borate glass system containing manganese and iron cations has been thoroughly investigated in order to obtain information about the mixed alkali effect and the structural role of both the manganese and iron in such glass hosts. Mixed alkali borate glasses of the (30 - x)Li(2)O - xK(2)O - 10CdO/ZnO - 59B(2)O(3) (x = 0, 10, 15, 20, and 30) doped with 1MnO(2)/1Fe(2)O(3) system were prepared by a melt quench technique. The amorphous phase of the prepared glass samples was confirmed from their X-ray diffraction. The spectroscopic properties of glass samples were studied using infrared (IR) and Raman spectroscopic techniques. The density of all the prepared glasses was measured using Archimedes principle. Molar volumes were estimated from the density data. IR spectra of these glasses revealed a dramatic variation of three- and four-coordinated boron structures as a function of mixed alkali concentration. The vibrations due to Li-O, K-O, and MnO(4)/FeO(4) arrangements are consistent in all the compositions and show a nonlinear variation in the intensity with alkali content. Raman spectra of different alkali combinations with CdO and ZnO present drastic changes in the intensity of various Raman bands. The observation of disappearance and reappearance of IR and Raman bands as a function of various alkali concentrations is an important result pertaining to the mixed alkali effect in borate glasses. Acting as complementary spectroscopic techniques, both types of measurements, IR and Raman, revealed that the network structure of the studied glasses is mainly based on BO(3) and BO(4) units placed in different structural groups, the BO(3) units being dominant. The measured IR and Raman spectra of different glasses are used to clarify the optical properties of the present glasses correlating them with their structure and composition. PMID:19235995

Padmaja, G; Kistaiah, P

2009-03-19

105

Crystal Nucleation in Lithium Borate Glass.  

National Technical Information Service (NTIS)

Crystal nucleation measurements were made on three lithium borate compositions in the vicinity of Li2O-2B2O3. All nucleation measurements were performed at 500 C. Certain aspects of the nucleation behavior indicated (tentatively) that it proceeded by a ho...

G. L. Smith G. F. Neilson M. C. Weinberg

1988-01-01

106

Strontium borate glass: potential biomaterial for bone regeneration  

PubMed Central

Boron plays important roles in many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the delivery of boron by the degradation of borate glass is of special interest in biomedical applications. However, the cytotoxicity of borate glass which arises with the rapid release of boron has to be carefully considered. In this study, it was found that the incorporation of strontium into borate glass can not only moderate the rapid release of boron, but also induce the adhesion of osteoblast-like cells, SaOS-2, thus significantly increasing the cyto-compatibility of borate glass. The formation of multilayers of apatite with porous structure indicates that complete degradation is optimistic, and the spread of SaOS-2 covered by apatite to form a sandwich structure may induce bone-like tissue formation at earlier stages. Therefore, such novel strontium-incorporated borosilicate may act as a new generation of biomaterial for bone regeneration, which not only renders boron as a nutritious element for bone health, but also delivers strontium to stimulate formation of new bones.

Pan, H. B.; Zhao, X. L.; Zhang, X.; Zhang, K. B.; Li, L. C.; Li, Z. Y.; Lam, W. M.; Lu, W. W.; Wang, D. P.; Huang, W. H.; Lin, K. L.; Chang, J.

2010-01-01

107

Broadband copper luminescence in potassium-aluminum borate glasses  

NASA Astrophysics Data System (ADS)

Broadband luminescence in the visible spectral range has been investigated for copper-containing potassium-aluminum borate glasses. It is shown that the luminescence in initial glasses (before their heat treatment) is due to the presence of molecular clusters Cu n ( n < 10) in them. Chemical reactions during heat treatment lead to the formation of Cu n Cl x and Cu n O x clusters with luminescence bands lying in the spectral range of 450-600 nm.

Nikonorov, N. V.; Sidorov, A. I.; Tsekhomskii, V. A.; Shakhverdov, T. A.

2013-03-01

108

Magnetic properties of ferrite microparticles in borate glasses  

NASA Astrophysics Data System (ADS)

Magneto-optic Faraday effect in potassium-alumina-borate glasses with Fe 2O 3 and CoO additions made during synthesis was studied in dependence on the light wavelength, external magnetic field an temperature. It was shown that unusual magnetic properties of these glasses were due to the formation of ferrimagnetic particles which behaved at definite conditions as an ansamble of noninterecting superparamagnetic particles. Dimensions, structure, composition and blocking temperature of the particles have been determined.

Edelman, I. S.; Zarubina, T. V.; Stepanov, S. A.; Kim, T. A.

1992-04-01

109

High-temperature relaxation spectra of borate glasses  

SciTech Connect

A critical analysis of a method for calculating the spectrum characteristics of mechanical relaxation in glass melts is given. The analysis of changes in the spectrum characteristics (in the Kohlrausch function approximation) for B{sub 2}O{sub 3} and sodium borate glasses within a broad temperature and frequency range allows us to ascertain the specific features of these changes due to structural factors.

Lomovskoi, V.A.; Bartenev, G.M. [Institute of Physical Chemistry, Moscow (Russian Federation)

1993-07-01

110

Structure of fast-ion-conducting lithium and sodium borate glasses by neutron diffraction and reverse Monte Carlo simulations  

NASA Astrophysics Data System (ADS)

The structures of fast-ion-conducting glasses (NaZ)x(Na2O-2B2O3)1-x and (LiZ)x(Li2O-2B2O3)1-x (Z=Cl,Br) have been examined by neutron diffraction and reverse Monte Carlo (RMC) simulations. The short-range structure of the boron-oxygen network is almost unchanged for increasing dopant salt concentration and independent of the dopant salt, whereas the intermediate range order of the B-O network decreases significantly for increasing dopant salt concentration. The sodium borate glasses are generally slightly more ordered than the corresponding lithium borate glasses. The differences may be explained by the fact that the Li-borate glasses consist of a disordered random mixture of many different types of borate configurations, while the Na-borate glasses are built up by randomly distributed diborate groups, as suggested previously from NMR results. The RMC simulations of the highest LiCl- and NaCl-doped glasses show, however, that large density fluctuations are present within the boron-oxygen network. The voids are of widely different sizes and geometrical shapes. The present findings show that the intermediate-range order of the LiCl- and NaCl-doped glasses is significantly different from that recently reported for the corresponding AgI-doped glass. For the latter the boron-oxygen network forms a more ordered chainlike structure with the salt ions cross linking between the ``chains.''

Swenson, J.; Börjesson, L.; Howells, W. S.

1998-06-01

111

Nuclear quadrupole resonance of boron in borate glasses  

NASA Astrophysics Data System (ADS)

A continuous wave nuclear quadrupole resonance spectrometer that has a high sensitivity even at low frequencies has been built. Boron and aluminum NQR has been detected in the region 200 kHz to 1.4 MHz. For the first time, boron NQR has been detected in a glass. The NQR spectrum of pure B 20 3 glass is consistent with 85 ± 2% of the boron atoms belonging to boroxol rings. In sodium borate glasses, the number of borons in boroxol rings decreases with increasing sodium content, until when sodium oxide comprises 20 mol% of the glass less than 2% of the borons are in boroxol rings.

Gravina, Samuel J.; Bray, Phillip J.

112

A comparison of HLW-glass and PWR-borate waste glass  

NASA Astrophysics Data System (ADS)

Glass can incorporate a wide variety of wastes ranging from high level wastes (HLW) to low and intermediate level wastes (LILW). A comparison of HLW-Glass and PWR-borate waste glass is given in this paper. The HLW glass formulation named GC-12/9B and 90-19/U can incorporate 16-20 wt% HLW at 1100°C or 1150°C. The borate waste glass named SL-1 can incorporate 45 wt% borate waste generated from PWR. Their physical properties, characteristic temperatures, chemical durability and leach behavior are summarized here. The comparison indicates: the PWR-glass SL-1 can incorporate up to 45 wt% waste oxides at lower melting temperature (1000°C) in agreement with minimum additive waste stabilization (MAWS) approach; owing to the PWR-borate glass contain less Si and more B and Na, its mass loss is higher than HWR-glass; both HLW-glass and PWR-borate glass have favorable chemical durability and the same leaching phenomena, i.e., Na is mostly depleted, but Ca, Mg, Al and Ti are enriched in the leached surface layer.

Luo, Shanggeng; Sheng, Jiawei; Tang, Baolong

2001-09-01

113

VO2+ ions in zinc lead borate glasses studied by EPR and optical absorption techniques.  

PubMed

Electron paramagnetic resonance (EPR) and optical absorption spectra of vanadyl ions in zinc lead borate (ZnO-PbO-B2O3) glass system have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of VO2+ ions. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in zinc lead borate glasses were present in octahedral sites with tetragonal compression and belong to C4V symmetry. The spin-Hamiltonian parameters g and A are found to be independent of V2O5 content and temperature but changing with ZnO content. The decrease in Deltag( parallel)/Deltag( perpendicular) value with increase in ZnO content indicates that the symmetry around VO2+ ions is more octahedral. The decrease in intensity of EPR signal above 10 mol% of V2O5 is attributed to a fall in the ratio of the number of V4+ ions (N4) to the number of V5+ ions (N5). The number of spins (N) participating in resonance was calculated as a function of temperature for VO2+ doped zinc lead borate glass sample and the activation energy was calculated. From the EPR data, the paramagnetic susceptibility was calculated at various temperatures and the Curie constant was evaluated from the 1/chi-T graph. The optical absorption spectra show single absorption band due to VO2+ ions in tetragonally distorted octahedral sites. PMID:16043053

Prakash, P Giri; Rao, J Lakshmana

2005-09-01

114

The leaching behavior of borate waste glass SL-1  

SciTech Connect

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak. It was found that the ion-exchange reactions dominated the glass corrosion process with water in low temperature leading conditions. The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching conditions. There was a peak in leach rate at about 70 C and a valley at about 100 C. The surface layer thickness was about 25 [micro]m. Na was almost totally depleted in the surface layer. At low temperature, the glass corrosion increases with leaching time. The glass corrosion remains about constant with leaching time at 90 C. The surface layer formed at 90 C is protective, which is less porous than the surface layer formed at 40 and 70 C.

Sheng, J. (Kyoto Univ., Osaka (Japan)); Luo, S.; Tang, B. (China Inst. of Atomic Energy, Beijing (China))

1999-01-01

115

The leaching behavior of borate waste glass SL-1  

SciTech Connect

Vitrification is an attractive approach for treatment of the borate waste from nuclear power plants. SL-1 glass is a suitable borosilicate glass form to solidify the borate waste containing relatively high quantities of B and Na. The leaching behavior of SL-1 glass in deionized water has been investigated. Compared to the HLW-glass, the network structure of SL-1 glass is weak. It was found that the ion-exchange reactions dominated the glass corrosion process with water in low temperature leading conditions. The ion-exchange and network hydrolysis reactions together controlled the glass dissolution in high temperature leaching conditions. There was a peak in leach rate at about 70 C and a valley at about 100 C. The surface layer thickness was about 25 {micro}m. Na was almost totally depleted in the surface layer. At low temperature, the glass corrosion increases with leaching time. The glass corrosion remains about constant with leaching time at 90 C. The surface layer formed at 90 C is protective, which is less porous than the surface layer formed at 40 and 70 C.

Sheng, J. [Kyoto Univ., Osaka (Japan)] [Kyoto Univ., Osaka (Japan); Luo, S.; Tang, B. [China Inst. of Atomic Energy, Beijing (China)] [China Inst. of Atomic Energy, Beijing (China)

1999-11-01

116

Synthesis and studies on microhardness of alkali zinc borate glasses  

NASA Astrophysics Data System (ADS)

The mixed alkali effect on zinc borate glasses have been reported. The glass systems of nominal composition 10Zn+xLi2O+yNa2O+80B2O3 (x = y = 0, 5, 10, 15 mol%) were prepared using standard melt quenching method. The structural, physical and mechanical properties of the samples have been studied using X-ray diffraction(XRD), density measurement and Vickers hardness measurement, respectively. A consistent increase in the density was observed, which explains the role of the modifiers (Li2O and Na2O) in the network modification of borate structure. The molar volume is decreasing linearly with the alkali concentration, which is attributed to the conversion of tetrahedral boron (BO4/2)- into (BO3/2)-. The microhardness studies reveals the anisotropy nature of the material. It further confirms that the samples belong to hard glass category.

Subhashini, Bhattacharya, Soumalya; Shashikala, H. D.; Udayashankar, N. K.

2014-04-01

117

Fluorescent borate glass superstrates for high efficiency CdTe solar cells  

NASA Astrophysics Data System (ADS)

Sm3+-doped barium borate glasses are investigated for their potential as a superstrate for CdTe solar cells. The influence of the Sm3+ conversion efficiency and the Sm2O3 doping level on the short circuit current density of a CdTe solar cell is analyzed. CdTe solar cells with CdS layer thicknesses of 45 and 300 nm are evaluated. A 3.2 mm thick, 2 mol% Sm2O3- doped glass superstrate enables a relative increase in the short circuit current density of approximately 1.4% and 2.9% for a 45 and 300 nm CdS buffer layer, respectively, assuming 100% Sm3+ conversion efficiency.

Steudel, Franziska; Dyrba, Marcel; Schweizer, Stefan

2012-05-01

118

Crystal nucleation in lithium borate glass  

NASA Technical Reports Server (NTRS)

Crystal nucleation measurements were made on three lithium borate compositions in the vicinity of Li2O-2Br2O3. All nucleation measurements were performed at 500 C. Certain aspects of the nucleation behavior indicated (tentatively) that it proceeded by a homogeneous mechanism. The steady state nucleation rate was observed to have the largest value when the Li2O concentration was slightly in excess of the diborate composition. The change in nucleation rate with composition is controlled by the variation of viscosity as well as the change in free energy with composition. The variation of nucleation rate is explained qualitatively in these terms.

Smith, Gary L.; Neilson, George F.; Weinberg, Michael C.

1988-01-01

119

Cell adhesion to borate glasses by colloidal probe microscopy.  

PubMed

The adhesion of osteoblast-like cells to silicate and borate glasses was measured in cell growth medium using colloidal probe microscopy. The probes consisted of silicate and borate glass spheres, 25-50 ?m in diameter, attached to atomic force microscope cantilevers. Variables of the study included glass composition and time of contact of the cell to the glasses. Increasing the time of contact from 15 to 900 s increased the force of adhesion. The data could be plotted linearly on a log-log plot of adhesive force versus time. Of the seven glasses tested, five had slopes close to 0.5, suggesting a square root dependence of the adhesive force on the contact time. Such behavior can be interpreted as a diffusion limited process occurring during the early stages of cell attachment. We suggest that the rate limiting step in the adhesion process is the diffusion of integrins resident in the cell membrane to the area of cell attachment. Data presented in this paper support the hypothesis of Hench et al. that strong adhesion depends on the formation of a calcium phosphate reaction layer on the surfaces of the glass. Glasses that did not form a calcium phosphate layer exhibited a weaker adhesive force relative to those glasses that did form a calcium phosphate layer. PMID:21241832

Wiederhorn, Sheldon M; Chae, Young-Hun; Simon, Carl G; Cahn, Jackson; Deng, Yan; Day, Delbert

2011-05-01

120

Temperature dependence of elastic properties in alkali borate binary glasses  

NASA Astrophysics Data System (ADS)

The elastic properties of alkali borate glasses, xM 2O·(100 - x)B 2O 3 (M = Li, Na, K, Rb, Cs, x = 14, 28), have been investigated by Brillouin scattering spectroscopy from room temperature up to 1100 °C. Above the glass transition temperature, Tg, the longitudinal sound velocity, VL, decreases markedly on heating. Such significant changes of the elastic properties result from the breakdown of the glass network above Tg. Alkali borate family with the same x shows the similar behavior in the temperature variations of VL up to around Tg. The absorption coefficient, ?L, increases gradually above Tg. With the increase of the size of an alkali ion, the slope of VL just above Tg decreases. Since the fragility is related to the slope, the present results suggest that the fragility of alkali borate glasses increases as the size of alkali ion decreases. Such an alkali dependence of the fragility is discussed on the basis of the fluctuation of the boron coordination number.

Kawashima, Mitsuru; Matsuda, Yu; Kojima, Seiji

2011-05-01

121

Laser spectroscopy of Nd 3+ and Dy 3+ ions in lead borate glasses  

NASA Astrophysics Data System (ADS)

The spectroscopic and laser properties of Nd 3+ and Dy 3+ ions in lead borate glass were studied. Luminescence spectra recorded in the near-infrared and visible ranges correspond to 4F 3/2- 4I J/2 ( J=9, 11, 13) transitions of Nd 3+ and 4F 9/2- 6H J/2 ( J=11, 13, 15) transitions of Dy 3+, respectively. Luminescence decay curves were analyzed as a function of activator concentration. Luminescence quenching is observed, which is due to Ln-Ln interaction increasing. Several spectroscopic parameters relevant to laser potential of Ln 3+ ions (Ln=Nd, Dy) in lead borate glass were determined. The relatively large values of the quantum efficiency and the room-temperature emission cross-section for the 4F 3/2- 4I 11/2 transition of Nd 3+ at 1061 nm and the 4F 9/2- 6H 13/2 transition of Dy 3+ at 573 nm imply that Ln-doped lead borate glasses can be considered as promising solid-state materials for laser applications.

Pisarska, Joanna; Pisarski, Wojciech A.; Ryba-Romanowski, Witold

2010-07-01

122

Visible luminescence of dysprosium ions in oxyhalide lead borate glasses.  

PubMed

Visible luminescence of Dy(3+) ions in oxyhalide lead borate glasses was examined. Luminescence spectra show two intense bands at 480 nm and 573 nm due to (4)F(9/2)?(6)H(15/2) (blue) and (4)F(9/2)?(6)H(13/2) (yellow) transitions of Dy(3+). Luminescence decays from (4)F(9/2) state and yellow-to-blue luminescence intensity ratios (Y/B) were analysed with PbX(2) (X=F, Cl) content. An introduction of PbX(2) to the borate glass results in the increasing of (4)F(9/2) lifetime and the decreasing of yellow-to-blue luminescence intensity ratio, which is due to reduction of covalency between Dy(3+) and O(2-)/X(-) ions. PMID:21036100

Pisarska, Joanna; ?ur, Lidia; Pisarski, Wojciech A

2011-08-15

123

XRD and FTIR studies the effect of heat treatment and doping the transition metal oxide on LiNbO3 and LiNb3O8 nano-crystallite phases in lithium borate glass system.  

PubMed

Glasses of various compositions in the system 90 Li2B4O7-10 Nb2O5 mixed with T.M ions (where T.M is the transition metal) were prepared by quenching technique. Heat-treatment of the parent glasses was performed at 540, 570 and 620 °C, for 5 and 16 h. The glass structure evolution during the controlled crystallization was examined by XRD and FT-IR spectroscopy analysis. The crystalline phases present in the glass ceramics were identified via X-ray diffraction as a function of heat treatment. The FT-IR data propose for these glasses and heat-treated glass network structures mainly built by: di-, tri-, tetra-, penta-and ortho-borate groups. It was found that the quantitative evolution of these various borate species in the glass structures is influenced by the transition metal. A detailed discussion relating to the N4 evolution with the T.M content was made. PMID:23708372

Kashif, Ismail; Soliman, Ashia A; Sakr, Elham M; Ratep, Asmaa

2013-09-01

124

XRD and FTIR studies the effect of heat treatment and doping the transition metal oxide on LiNbO3 and LiNb3O8 nano-crystallite phases in lithium borate glass system  

NASA Astrophysics Data System (ADS)

Glasses of various compositions in the system 90 Li2B4O7sbnd 10 Nb2O5 mixed with T.M ions (where T.M is the transition metal) were prepared by quenching technique. Heat-treatment of the parent glasses was performed at 540, 570 and 620 °C, for 5 and 16 h. The glass structure evolution during the controlled crystallization was examined by XRD and FT-IR spectroscopy analysis. The crystalline phases present in the glass ceramics were identified via X-ray diffraction as a function of heat treatment. The FT-IR data propose for these glasses and heat-treated glass network structures mainly built by: di-, tri-, tetra-, penta-and ortho-borate groups. It was found that the quantitative evolution of these various borate species in the glass structures is influenced by the transition metal. A detailed discussion relating to the N4 evolution with the T.M content was made.

Kashif, Ismail; Soliman, Ashia A.; Sakr, Elham M.; Ratep, Asmaa

2013-09-01

125

Barium–borate–flyash glasses: As radiation shielding materials  

Microsoft Academic Search

The attenuation coefficients of barium–borate–flyash glasses have been measured for ?-ray photon energies of 356, 662, 1173 and 1332keV using narrow beam transmission geometry. The photon beam was highly collimated and overall scatter acceptance angle was less than 3°. Our results have an uncertainty of less than 3%. These coefficients were then used to obtain the values of mean free

Sukhpal Singh; Ashok Kumar; Devinder Singh; Kulwant Singh Thind; Gurmel S. Mudahar

2008-01-01

126

Photostimulated decay of radiation color centers in alkali borate glasses  

SciTech Connect

The decay of color centers in alkali borate glasses exposed to polarized optical radiation is studied. Optical irradiation of {gamma}-colored glasses is shown to destruct all types of color centers investigated. The mechanism of decay is defined by the type of color centers excited by a given type of radiation. Decay may be due either to photoionization of electron-type centers and subsequent recombination of the released electrons with hole-type centers or to delocalization of holes from hole-type centers and their subsequent recombination with electrons from electron-type centers.

Barinova, N.A.; Glebov, L.B. [Research and Technological Institute of Optical Materials Science, St. Petersburg (Russian Federation)

1994-05-01

127

Photoluminescence of a Te4+ center in zinc borate glass.  

PubMed

Photoluminescent (PL) properties related to Te(4+) species in zinc borate glasses are examined. Broad emission was observed by the excitation of the PL excitation peak of Te(4+) present at the optical absorption edge. The emission intensity of Te(4+) in 5TeO(2)-50ZnO-45B(2)O(3) glass was thermally quenched in a temperature region over 100 K, suggesting that concentration quenching preferentially occurred. The lifetime of the emission was approximately 2.5 ?s, which is characteristic of relaxation from the triplet excitation state of an ns(2)-type center. PMID:24081051

Masai, Hirokazu; Yamada, Yasuhiro; Okumura, Shun; Kanemitsu, Yoshihiko; Yoko, Toshinobu

2013-10-01

128

Optical study of Ce 3+ ion in gamma-irradiated binary barium-borate glasses  

Microsoft Academic Search

Absorption spectra measurements of cerium-doped binary system from barium-borate glasses have been measured. The effects of dopant concentration of CeO2 and Al2O3 in the concentration range 0.54–2.9 and 4.8–9.2mol%, respectively, and exposed to different irradiation doses have been measured in the range 1–7eV and the result have been interpreted in terms of structural concepts. The radiation-induced broad band at 2.25–1.88eV

S. Y. Marzouk; F. M. Ezz-Eldin

2008-01-01

129

Raman and Infrared Spectroscopy of Yttrium Aluminum Borate Glasses and Glass-ceramics  

NASA Technical Reports Server (NTRS)

Raman spectra of glasses and glass-ceramics in the Y2O3-Al2O3-B2O3 system are reported. Glasses with B2O3 contents ranging from 40 to 60 mole percent were prepared by melting 20 g of the appropriate oxide or carbonate powders in alumina crucibles at 1400 C for 45 minutes. Subsequent heat treatments of the glasses at temperatures ranging from 600 to 800 C were performed in order to induce nucleation and crystallization. It was found that Na2CO3 added to the melt served as a nucleating agent and resulted in uniform bulk crystallization. The Raman spectra of the glasses are interpreted primarily in terms of vibrations of boron - oxygen structural groups. Comparison of the Raman spectra of the glass-ceramic samples with spectra of aluminate and borate crystalline materials reveal that these glasses crystallize primarily as yttrium aluminum borate, YAl3(BO3)4.

Bradley, J.; Brooks, M.; Crenshaw, T.; Morris, A.; Chattopadhyay, K.; Morgan, S.

1998-01-01

130

Optical and FT Infrared spectral studies of vanadium ions in cadmium borate glass and effects of gamma irradiation.  

PubMed

Combined optical and infrared absorption spectra of V2O5-doped cadmium borate glasses were investigated before and after gamma irradiation with a dose of 8 Mrad (=8×10(4) Gy). The undoped base cadmium borate glass reveals a spectrum consisting of strong charge transfer UV absorption bands which are related to the presence of unavoidable contaminated trace iron impurities (mainly Fe(3+)). The V2O5-doped glasses reveal an extra band at 380nm and the high V2O5-content glass also shows a further band at about 420nm. The observed optical spectrum indicates the presence of vanadium ions mainly in the pentavalent state (d(0) configuration). The surplus band at 420nm shows that some trivalent vanadium ions are identified at high V2O5 content. The optical spectra of the glasses after gamma irradiation show small decrease of the intensity of the UV absorption which are interpreted by assuming the transformation of some Fe(3+) ions by photochemical reactions with the presence of high content (45mol%) of heavy massive CdO causing some shielding behavior. FT infrared absorption spectra of the glasses show vibrational bands due to collective presence of triangular and tetrahedral borate groups in their specific wavenumbers. The FTIR spectra are observed to be slightly affected by both the V2O5-dopants being present in modifying low percent or gamma irradiation due to the presence of high content heavy CdO. PMID:24840491

AbdelAziz, T D; EzzElDin, F M; El Batal, H A; Abdelghany, A M

2014-10-15

131

Conductivity and dielectric relaxation in niobium alkali borate glasses  

NASA Astrophysics Data System (ADS)

The frequency and temperature dependent conductivity investigations for alkali niobium borate glasses of composition xNb 2O 5·(30- x)M 2O·70B 2O 3 (where M=Li, Na; x=0, 4, 8 mol%) have been carried out using impedance spectroscopy (IS). The complex impedance data have been analyzed by using both the conductivity and the electric modulus formalisms. The conductivity decreases with the decrease in M 2O:Nb 2O 5 ratio. The effect of temperature on the scaling of dielectric modulus indicates that the conductivity relaxation mechanism is temperature independent. The overlapping of the normalized peaks corresponding to impedance and electric modulus and the identical values of thermal activation energy for conduction and relaxation suggest the single mechanism for the dynamic processes occurring in the present glasses. The variation of density, molar volume and glass transition temperature with glass composition has also been reported to supplement the conductivity results.

Sanghi, Sujata; Sheoran, Anshu; Agarwal, Ashish; Khasa, Satish

2010-12-01

132

Structural properties of molybdenum-lead-borate glasses.  

PubMed

Glasses and glass ceramics in the system xMoO?·(100 - x)[3B?O?·PbO] with 0 ? x ? 30 mol% have been prepared from melt quenching method and characterized by means of X-ray diffraction, FTIR, UV-VIS and EPR spectroscopy. We have examined and analyzed the effects of systematic molybdenum ions intercalation on lead-borate glasses and glass ceramics with interesting results. The observations present in these mechanisms show the lead ions bonded ionic have a strong affinity towards [BO?] units containing non-bridging oxygens and [MoO?]²? molybdate units. The pronounced affinity towards molybdate anions yields the formation of the PbMoO? crystalline phase. Then, the excess of oxygen can be supported into the glass network by the formation of [MoO?] and [Mo?O?] structural units. Pb²(+) ions with 6s² configuration show strong absorption in the ultraviolet due to parity allowed s²-sp transition and yield an absorption band centered at about 310 nm. The changes in the features of the absorption bands centered at about 310 nm can be explained as a consequence of the appearance of additional absorption shoulder due to photoinduced color centers in the glass such as the formation of borate-molybdate and lead-molybdate paramagnetic defect centers in the glasses. The concentration of molybdenum ions influences the shape and width of the EPR signals located at g ? 1.86, 1.91 and 5.19. The microenvironment of molybdenum ions in glasses is expected to have mainly sixfold coordination. However, there is a possibility of reduction of a part of molybdenum ions from the Mo?(+) to the Mo?(+) and Mo?(+) to the Mo³(+) states. PMID:20817593

Rada, M; Rada, S; Pascuta, P; Culea, E

2010-11-01

133

Luminescence properties of Sm{sup 3+} impurities in strontium lithium bismuth borate glasses  

SciTech Connect

In the present work, different concentrations of Sm{sup 3+}-doped strontium lithium bismuth borate glasses (SLBiB) were prepared by melt quench technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. Using the J-O intensity parameters, emission and decay measurements various radiative properties are studied. The nature of decay curves of {sup 4}G{sub 5/2} level for different Sm{sup 3+} ion concentrations in SLBiB glasses has been analyzed. The intensities of observed emission peaks and measured lifetimes decrease with the increase of Sm{sup 3+} ion concentration which may be due to energy transfer between excited Sm{sup 3+} ions through cross-relaxations and resonant energy channels.

Rajesh, D.; Ratnakaram, Y. C.; Seshadri, M.; Balakrishna, A. [Department of Physics,Sri Venkateswara University,Tirupati-517502 (India)

2012-06-05

134

Luminescence properties of Sm3+ impurities in strontium lithium bismuth borate glasses  

NASA Astrophysics Data System (ADS)

In the present work, different concentrations of Sm3+-doped strontium lithium bismuth borate glasses (SLBiB) were prepared by melt quench technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction and SEM analysis. Using the J-O intensity parameters, emission and decay measurements various radiative properties are studied. The nature of decay curves of 4G5/2 level for different Sm3+ ion concentrations in SLBiB glasses has been analyzed. The intensities of observed emission peaks and measured lifetimes decrease with the increase of Sm3+ ion concentration which may be due to energy transfer between excited Sm3+ ions through cross-relaxations and resonant energy channels.

Rajesh, D.; Ratnakaram, Y. C.; Seshadri, M.; Balakrishna, A.

2012-06-01

135

Preparation and properties of porous microspheres made from borate glass.  

PubMed

Dysprosium lithium-borate glass microspheres and particles, ranging from 45 to 150 microm in diameter, were reacted with a 0.25 M phosphate solution at 37 degrees C, whose pH was either 3 or 8.8. The glass reacted nonuniformly and was converted into a porous, amorphous, hydrated, dysprosium phosphate reaction product. The amorphous product had the same volume and shape (pseudomorphic) as the unreacted glass, and could be dried without cracking. After heating at 300 degrees C for 1 h, the amorphous reaction product had a specific surface area of approximately 200 m(2)/g, a pore size of approximately 30 nm, and nominal crushing strength of approximately 10 MPa. When the reaction product was heated to 600 degrees C for 15 min, the specific surface area decreased to approximately 90 m(2)/g and the nominal crushing strength increased to 35 MPa. Heating above 615 degrees C converted the amorphous dysprosium phosphate product into crystalline DyPO(4), which contained open porosity until heated above 800 degrees C for 15 min. Highly porous materials of different chemical composition can be prepared by chemically reacting a borate-based glass with an aqueous solution at low-temperature (<100 degrees C). These highly porous materials are easy to process, and are considered candidates for controlled drug delivery, catalysis, chromatographic separation, filtration, and as bioactive materials. PMID:18306308

Conzone, Samuel D; Day, Delbert E

2009-02-01

136

Structure and surface chemistry of borate and boroaluminate glasses  

NASA Astrophysics Data System (ADS)

The short and intermediate range structure of boroaluminate glasses has been investigated using solid state magic angle spinning nuclear magnetic resonance (MAS NMR). It was found that the aluminum ion may exhibit 4, 5, and 6-fold coordination. It was also shown that the aluminum can adopt the role of both a modifier and network former in the glass backbone. The dependence of the local aluminum structure on composition is discussed. The intermediate range order in barium boroaluminate glasses was directly probed using solid state double resonance NMR experiments. It was found that connections between (AlOsb{4/2})sp- and (BOsb{4/2})sp- units are strongly discouraged. This restriction affects the short range order of the boron atoms in the glass since it places a constraint on the maximum number of possible tetrahedral boron and aluminum-oxide polyhedra in the glass. The surface structure and chemistry in borate and boroaluminate glasses has been investigated. X-ray photoelectron spectroscopy (XPS), low energy ion scattering spectroscopy (ISS) and sp1H->sp{11}B cross polarization (CP) MAS NMR have been used in the surface characterization. O 1s and B 1s chemical shifts in the XPS spectra were described using a modified Sanderson model for the calculation of charge density. A peak corresponding to non-bridging oxygens (NBO) in the borate glasses was identified and used to quantify the NBO density. ISS analyses of the outermost atomic layer of clean vacuum fracture surfaces showed that relaxation of the surface atoms occurs during or shortly after the fracture event. The surface was found to be depleted in modifying cations, in contrast to silicate glasses. This is thought to be due to a conversion of tetrahedral units to trigonal coordination in an effort to reduce surface energy. Melt surfaces and graphite interfaces were found to exhibit chemical deviations from the corresponding fracture surfaces. The chemical shifts in the XPS spectra were consistent with enrichment of trigonally-coordinated boron-oxide units at the melt and interface surfaces. ISS and CP MAS NMR analyses of borate glass surfaces formed at high temperatures also provide direct evidence of structural rearrangement concordant with the geometrical optimization of the planar BOsb3 groups at the surface.

Beall, Douglas Munroe

137

Optical properties of bismuth borate glasses  

Microsoft Academic Search

Optical properties of glasses in the binary system bismuth oxide (Bi2O3)–boric oxide (B2O3) are measured for the composition range 25–65 mol% Bi2O3. Both, refractive indices and ultraviolet absorption edge, show an expressed dependence on composition. A generalized Sellmeier formula is derived to describe the refractive indices for the whole composition range and a wide wavelength range.

Isabella-Ioana Oprea; Hartmut Hesse; Klaus Betzler

2004-01-01

138

HYSCORE spectroscopy in the borate glasses  

Microsoft Academic Search

Glasses of the composition xB2O3–Li2O, with x=1, 2, 3, 4 and 5 were exposed to 60Co ?-irradiation and measured with hyperfine sublevel correlation (HYSCORE) spectroscopy. The HYSCORE spectra were explained with the assistance of a simulation procedure developed in-house in order to extract important parameters describing the Hamiltonian of the second boron neighbor of the paramagnetic state. HYSCORE spectroscopy in

George Kordas

2003-01-01

139

Preparation of crystalline beta barium borate thin films on Sr 2+-doped alpha barium borate substrates by liquid phase epitaxy  

Microsoft Academic Search

Thin films of beta barium borate have been prepared by liquid phase epitaxy on Sr2+-doped ?-BaB2O4 (?-BBO, the high temperature phase of barium borate) (001) and (110) substrates. The results of X-ray diffraction indicate that the films show highly (00l) preferred orientation on (001)-oriented substrates while the films grown on (110) substrates are textured with (140) orientation. The crystallinity of

Junfang Liu; Xiaoming He; Changtai Xia; Guoqing Zhou; Shengming Zhou; Jun Xu; W. Yao; Liejia Qian

2006-01-01

140

Thermal, structural and electrical studies of bismuth zinc borate glasses  

NASA Astrophysics Data System (ADS)

Bismuth Zinc Borate glasses with compositions xBi2O3-30ZnO-(70 - x)B2O3 (where x = 30, 35, 40 and 45 mol %) have been prepared by melt quenching method. These glasses were characterized by X-ray diffraction (XRD), Differential Thermal Analysis (DTA), Fourier Transform Infrared Spectrometer (FTIR) and Broad Band Dielectric Spectrometer (BDS). DTA and FTIR analysis reveals that Non-Bridging Oxygens (NBOs) increase with increase of bismuth content in the glass. Electrical data have been analyzed in the framework of impedance and modulus formalisms. The activation energy for dc conductivity decreases with increase of bismuth concentration. The imaginary part of modulus spectra has been fitted to non-exponential Kohlrausch-Williams-Watts (KWW) function and the value of the stretched exponent (?) is found to be almost independent of temperature but slightly dependent on composition.

Shanmugavelu, B.; Ravi Kanth Kumar, V. V.

2013-06-01

141

Structural and acoustic investigations of calcium borate glasses  

NASA Astrophysics Data System (ADS)

Acoustic and structural properties of x CaO . (1-x ) B2O3 (0.2 x 0.7) glass system have been studied at ambient temperature. The ultrasonic velocity and attenuation for different compositions of calcium borate glasses were measured at 5 MHz at room temperature (303 K) using a pulse echo overlap method. The elastic moduli, Debye temperature, Poisson's ratio and other acoustic parameters have been obtained from experimental data. Fourier transform infrared spectroscopic analysis has been used to further support the results of acoustic studies. The results obtained indicate that the calcium oxide enters the glass network as a modifier by occupying the interstitial spaces in the network and by increasing the nonbridging oxygen atoms (NBOs).

Manupriya; Thind, K. S.; Sharma, G.; Rajendran, V.; Singh, K.; Gayathri Devi, A. V.; Aravindan, S.

2006-08-01

142

Preparation and characterization of magnesium borate for special glass  

NASA Astrophysics Data System (ADS)

Magnesium borate with a variety of B2O3/MgO molar ratios, which can be applied for special glass, has been prepared through the reaction of light-burned magnesia with boric acid by a hydrothermal method. The effects of the B2O3/MgO molar ratio of raw materials, reaction time, temperature and liquid to solid ratio (ml g-1) on the synthetic product are investigated. The XRD and TG-DTG analyses indicate that the prepared magnesium borate is a mixture of magnesium hexaborate hydrate and ascharite. The results show that high B2O3/MgO molar ratios of raw materials and low reaction liquid-solid ratios favour the product with a high B2O3/MgO molar ratio and vice versa. There exists free MgO in the product when the reaction temperature is below 140 °C or the reaction time is not enough, because of the incomplete reaction of magnesium oxide with boric acid. The process of fractional crystallization for the magnesium borate mixture is also discussed.

Dou, Lishuang; Zhong, Jianchu; Wang, Hongzhi

2010-05-01

143

Ultrasonic relaxations, anharmonicity, and fragility in lithium borate glasses  

NASA Astrophysics Data System (ADS)

The attenuation and velocity of ultrasonic waves of frequencies in the range of 10to70MHz have been measured in (Li2O)x(B2O3)1-x borate glasses as a function of temperature between 1.5 and 300K . Two distinct features characterize the attenuation behavior: (i) a plateau at temperatures below 10K , (ii) a broad high-temperature peak. The former feature is interpreted in terms of the phonon-assisted relaxation of two level systems and the latter by assuming the existence of a distribution of thermally activated relaxing centers. The spectral density of two-level systems results to be independent on the alkali oxide content, while the density of relaxing particles decreases with increasing lithium ion concentration supporting their association to the triangular BO?3 units building up the borate skeleton ( O?=oxygen atom bridging between two network-forming ions, i.e., boron ions). The comparison between the number densities of two-level systems and of relaxing particles indicates that only a small fraction of the locally mobile defects are subjected to tunneling motions. At temperatures below 100K the sound velocity is mainly governed by the relaxation contribution, while above 100K it is regulated by the vibrational anharmonicity and shows a nearly linear temperature dependence, whose slope strongly depends on the concentration of network modifier ions ( Li+ ions). The determination of the average thermal Grüneisen parameters permits us also to disclose the existence of a distinct correlation between anharmonicity and fragility of lithium borate glasses: a growing fragility is predictive of an increasing anharmonicity.

Carini, Giovanni; Carini, Giuseppe; D'Angelo, Giovanna; Tripodo, Gaspare; Bartolotta, Antonio; Salvato, Gabriele

2005-07-01

144

Effect of TiO2 on electron paramagnetic resonance, optical transmission and dc conductivity of vanadyl doped sodium borate glasses.  

PubMed

Glass systems with composition xTiO2.(30 - x)Na2O.70B2O3 (series I) and xTiO2.(70 - x)B2O3.30Na2O (series II) containing 2 mol% V2O5 have been prepared (0 < or = x < or = 7, mol%) by normal melt-quenching. The electron paramagnetic resonance (EPR) spectra of VO2+ ions have been recorded in the X-band (approximately 9.13 GHz) at room temperature. Spin Hamiltonian parameters, gparallel, gperpendicular, Aparallel, Aperpendicular, the dipolar hyperfine coupling parameter (P) and the Fermi contact interaction parameter (K) have been calculated. The increase in Deltagparallel/Deltagperpendicular with increase in TiO2 content in series I shows that the octahedral symmetry of V4+O6 complex is reduced, whereas in series II the octahedral symmetry is improved with increase in x. The decrease in P, in both the series, indicates that the 3dxy orbit expands with increase in mol% of TiO2. The molecular orbital coefficients, alpha2 and gamma2 have been calculated by recording the optical transmission spectra in the range 500-850 nm. alpha2 and gamma2 increase with increase in x in both the series, which indicates that, the covalency of the vanadium oxygen bonds decreases. The dc conductivity sigma, decreases and activation energy, W increases with increase in TiO2:Na2O ratio whereas with increase in TiO2:B2O3 ratio the variation in sigma and W is within experimental error. PMID:15477159

Agarwal, A; Seth, V P; Gahlot, P; Goyal, D R; Arora, M; Gupta, S K

2004-11-01

145

Ytterbium-doped borate fluoride laser crystals and lasers  

DOEpatents

A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM'(BO.sub.3)F, where M, M' are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO.sub.3 F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator.

Schaffers, Kathleen I. (Pleasanton, CA); DeLoach, Laura D. (Manteca, CA); Payne, Stephen A. (Castro Valley, CA); Keszler, Douglas A. (Corvallis, OK)

1997-01-01

146

Ytterbium-doped borate fluoride laser crystals and lasers  

DOEpatents

A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM{prime}(BO{sub 3})F, where M, M{prime} are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO{sub 3}F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator. 6 figs.

Schaffers, K.I.; DeLoach, L.D.; Payne, S.A.; Keszler, D.A.

1997-10-14

147

Optical study of Ce 3+ ion in gamma-irradiated binary barium-borate glasses  

NASA Astrophysics Data System (ADS)

Absorption spectra measurements of cerium-doped binary system from barium-borate glasses have been measured. The effects of dopant concentration of CeO 2 and Al 2O 3 in the concentration range 0.54-2.9 and 4.8-9.2 mol%, respectively, and exposed to different irradiation doses have been measured in the range 1-7 eV and the result have been interpreted in terms of structural concepts. The radiation-induced broad band at 2.25-1.88 eV in the base glass is observed to be suppressed by the presence of cerium due to the transformation of Ce 4+ to Ce 3+. The released electrons are then used to annihilate positive holes responsible for this band. The resolution of the observed absorption spectra show two to seven induced bands depending on the glass composition. Absorption spectra of the irradiated binary glass system are found to be controlled by the cerium concentration. From the absorption edge studies, the values of optical band gap Eopt and Urbach energy ? E have been evaluated. The oxidoreduction (redox) reaction Ce 3+/Ce 4+ is assumed to be related to the glass basicity and the possible complex-ion formation. The oxygen ion activity (O 2-) is believed to be related to the basicity and to the possible oxygen ion formation in the glass melt, and the redox equilibrium is shifted toward the reduced state.

Marzouk, S. Y.; Ezz-Eldin, F. M.

2008-09-01

148

Persistent spectral hole burning of Sm 2+ in borate glasses  

Microsoft Academic Search

It is expected that persistent spectral hole burning (PSHB) will be applied for a high-density data storage system and it can serve as a powerful method for studying the local structure around optical centers. The authors' group has discovered a room-temperature PSHB material for Sm2+-doped glasses. The present work investigated the relationship between the Debye temperature of the glass and

D. H. Cho; K. Hirao; N. Soga

1995-01-01

149

Electron paramagnetic resonance and optical absorption studies of Fe(III) ions in alkali barium borate glasses  

Microsoft Academic Search

Electron paramagnetic resonance (EPR) and optical absorption studies of Fe(III) ions doped in 20 M2O+(25?x) BaO+55B2O3+xFe2O3 (M=Li, Na or K, 0.25?x?10) glasses were carried out. The EPR spectra have resonances at g=10±0.5, g=6.4±0.1, g=4.2±0.1 and g=2.0±0.1. The EPR spectra of x=0.5 mol% of Fe2O3 in sodium–barium borate glass sample was studied at various temperatures. The linewidths were found to be

R. P Sreekanth Chakradhar; A Murali; J Lakshmana Rao

1998-01-01

150

Nuclear Magnetic Resonance in Thallium Borate Glasses. I. The Thallium-205 Chemical Shift.  

National Technical Information Service (NTIS)

Chemical shift measurements on 205Tl in thallium borate glasses at temperatures up to and above the softening temperature (300C) indicate that the interactions of Tl(I) with oxygen atoms in the borate network are predominantly ionic. There is relatively l...

R. K. Momii N. H. Nachtrieb

1968-01-01

151

Narrow energy gap between triplet and singlet excited states of Sn2+ in borate glass.  

PubMed

Transparent inorganic luminescent materials have attracted considerable scientific and industrial attention recently because of their high chemical durability and formability. However, photoluminescence dynamics of ns(2)-type ions in oxide glasses has not been well examined, even though they can exhibit high quantum efficiency. We report on the emission property of Sn(2+)-doped strontium borate glasses. Photoluminescence dynamics studies show that the peak energy of the emission spectrum changes with time because of site distribution of emission centre in glass. It is also found that the emission decay of the present glass consists of two processes: a faster S1-S0 transition and a slower T1-S0 relaxation, and also that the energy difference between T1 and S1 states was found to be much smaller than that of (Sn, Sr)B6O10 crystals. We emphasize that the narrow energy gap between the S1 and T1 states provides the glass phosphor a high quantum efficiency, comparable to commercial crystalline phosphors. PMID:24345869

Masai, Hirokazu; Yamada, Yasuhiro; Suzuki, Yuto; Teramura, Kentaro; Kanemitsu, Yoshihiko; Yoko, Toshinobu

2013-01-01

152

Narrow Energy Gap between Triplet and Singlet Excited States of Sn2+ in Borate Glass  

NASA Astrophysics Data System (ADS)

Transparent inorganic luminescent materials have attracted considerable scientific and industrial attention recently because of their high chemical durability and formability. However, photoluminescence dynamics of ns2-type ions in oxide glasses has not been well examined, even though they can exhibit high quantum efficiency. We report on the emission property of Sn2+-doped strontium borate glasses. Photoluminescence dynamics studies show that the peak energy of the emission spectrum changes with time because of site distribution of emission centre in glass. It is also found that the emission decay of the present glass consists of two processes: a faster S1-S0 transition and a slower T1-S0 relaxation, and also that the energy difference between T1 and S1 states was found to be much smaller than that of (Sn, Sr)B6O10 crystals. We emphasize that the narrow energy gap between the S1 and T1 states provides the glass phosphor a high quantum efficiency, comparable to commercial crystalline phosphors.

Masai, Hirokazu; Yamada, Yasuhiro; Suzuki, Yuto; Teramura, Kentaro; Kanemitsu, Yoshihiko; Yoko, Toshinobu

2013-12-01

153

Narrow Energy Gap between Triplet and Singlet Excited States of Sn2+ in Borate Glass  

PubMed Central

Transparent inorganic luminescent materials have attracted considerable scientific and industrial attention recently because of their high chemical durability and formability. However, photoluminescence dynamics of ns2-type ions in oxide glasses has not been well examined, even though they can exhibit high quantum efficiency. We report on the emission property of Sn2+-doped strontium borate glasses. Photoluminescence dynamics studies show that the peak energy of the emission spectrum changes with time because of site distribution of emission centre in glass. It is also found that the emission decay of the present glass consists of two processes: a faster S1-S0 transition and a slower T1-S0 relaxation, and also that the energy difference between T1 and S1 states was found to be much smaller than that of (Sn, Sr)B6O10 crystals. We emphasize that the narrow energy gap between the S1 and T1 states provides the glass phosphor a high quantum efficiency, comparable to commercial crystalline phosphors.

Masai, Hirokazu; Yamada, Yasuhiro; Suzuki, Yuto; Teramura, Kentaro; Kanemitsu, Yoshihiko; Yoko, Toshinobu

2013-01-01

154

On the Elastic behavior of Sodium Borate Glasses  

NASA Astrophysics Data System (ADS)

Alkali Borates are industrial glasses and their physical properties are of general interest. We have made a special effort to synthesize dry (Na2O)x(B2O3)100-x glasses over a wide composition range, 0 < x < 70%, and have examined them in modulated-DSC, Raman scattering, FTIR, and molar volume experiments. The enthalpy of relaxation at Tg shows a global minimum in the 20% < x < 40% range, which we identify with the rigid but stress-free Intermediate Phase (IP). The Boroxyl ring vibrational mode near 808 cm-1 in B2O3, steadily softens by about 4 cm-1 as the soda content increases to about 20%. A vibrational mode of mixed ringsfootnotetextKamitsos et al., Jour. Mol. Struct 247, 1 (1996). (containing 3-fold and 4-fold B) is also observed near 775 cm-1 at low x, and it also steadily softens by nearly 10 cm-1 as x increases in the 20% < x < 40% soda range (IP). We are examining the underlying optical elasticity power-laws to ascertain the nature of the elastic phases. IR reflectance experiments provide the 4-fold coordinated B fraction to increase from 0.17 near x = 20% to 0.44 near x = 40% in broad agreement with NMR results. Evolution of physical properties of these glasses with soda content will be reviewed.

Vignarooban, K.; Boolchand, P.; Kerner, R.; Micoulaut, M.

2010-03-01

155

Raman Spectra of Yttrium Aluminum Borate Glasses and Glass-Ceramics  

NASA Astrophysics Data System (ADS)

Raman spectra of glasses and glass-ceramics in the Y_2O_3-Al_2O_3-B_2O3 system are reported. Glasses with B_2O3 contents ranging from 40 to 60 mole percent were prepared by melting 20 g of the appropriate oxide or carbonate powders in alumina crucibles at 1400^oC for 45 minutes. Subsequent heat treatments of the glasses at temperatures ranging from 600 to 700^oC were performed in order to induce nucleation and crystallization. It was found that Na_2CO3 added to the melt served as a nucleating agent and resulted in uniform bulk crystallization. The Raman spectra of the glasses are interpreted primarily in terms of vibrations of boron - oxygen structural groups. Comparison of the Raman spectra of the glass-ceramic samples with spectra of aluminate and borate crystalline materials reveal that these glasses crystallize primarily as yttrium aluminum borate, YAl_3(BO_3)_4.

Bradley, Juronica; Brooks, Montel; Crenshaw, Tiffany; Morris, Ayesha; Morgan, Steven

1997-11-01

156

Composition dependence of glass transition temperature and fragility. II. A topological model of alkali borate liquids  

NASA Astrophysics Data System (ADS)

Glass transition temperature and fragility are two important properties derived from the temperature dependence of the shear viscosity of glass-forming melts. While direct calculation of these properties from atomistic simulations is currently infeasible, we have developed a new topological modeling approach that enables accurate prediction of the scaling of both glass transition temperature and fragility with composition. A key feature of our approach is the incorporation of temperature-dependent constraints that become rigid as a liquid is cooled. Using this approach, we derive analytical expressions for the composition (x) dependence of glass transition temperature, Tg(x), and fragility, m(x), in binary alkali borate systems. Results for sodium borate and lithium borate systems are in agreement with published values of Tg(x) and m(x). Our modeling approach reveals a natural explanation for the presence of the constant Tg regime observed in alkali borate systems.

Mauro, John C.; Gupta, Prabhat K.; Loucks, Roger J.

2009-06-01

157

Composition dependence of glass transition temperature and fragility. II. A topological model of alkali borate liquids.  

PubMed

Glass transition temperature and fragility are two important properties derived from the temperature dependence of the shear viscosity of glass-forming melts. While direct calculation of these properties from atomistic simulations is currently infeasible, we have developed a new topological modeling approach that enables accurate prediction of the scaling of both glass transition temperature and fragility with composition. A key feature of our approach is the incorporation of temperature-dependent constraints that become rigid as a liquid is cooled. Using this approach, we derive analytical expressions for the composition (x) dependence of glass transition temperature, T(g)(x), and fragility, m(x), in binary alkali borate systems. Results for sodium borate and lithium borate systems are in agreement with published values of T(g)(x) and m(x). Our modeling approach reveals a natural explanation for the presence of the constant T(g) regime observed in alkali borate systems. PMID:19548735

Mauro, John C; Gupta, Prabhat K; Loucks, Roger J

2009-06-21

158

A new study on bismuth doped oxide glasses.  

PubMed

Spectroscopic properties of bismuth doped borate, silicate and phosphate glasses have been reinvestigated in this work. It shows the typical decay time of Bi(3+) is around 500ns rather than 2.7-to-3.9 ?s reported by Parke and Webb at room temperature. Introduction of higher content either alkali or alkali earth into borate glasses favors the Bi(3+) emission. As the contents increase excitation peak shifts regularly red while emission peak shows reverse trend. This, as revealed by Huang-Rhys factor, is due to the weakening of coupling between bismuth and glass host, and it can be interpreted within the frame of configurational coordinate diagrams. Differently, as bismuth concentration increases, both the excitation and emission shift red. The unknown origin of red emission from bismuth doped calcium or magnesium phosphate glass has been identified as Bi(2+) species on the basis of excitation spectrum and emission lifetime particularly after comparing with Bi(2+) doped materials. No near infrared (NIR) emission can be detected in these glasses within instrument limit. PMID:22772261

Xu, Wenbin; Peng, Mingying; Ma, Zhijun; Dong, Guoping; Qiu, Jianrong

2012-07-01

159

Structural studies of solution-made high alkali content borate glasses  

Microsoft Academic Search

The glass forming range of alkali borates has been extended to R=5.0 (83mol% alkali oxide) using a solution method. This method involves the reaction between solutions of boric acid (H3BO3) and alkali hydroxide (MOH). Physical properties and NMR studies were performed on the intermediate and final glass products of this method. We have obtained results for the entire alkali borate

Joy Banerjee; Greg Ongie; Jacob Harder; Trenton Edwards; Chris Larson; Scott Sutton; Anthony Moeller; Abhirup Basu; Mario Affatigato; Steve Feller; Masao Kodama; Pedro M. Aguiar; Scott Kroeker

2006-01-01

160

Physical properties of barium borate glasses determined over a wide range of compositions  

Microsoft Academic Search

Barium borate glasses are reported over an extended glass-forming range from R=0.2 (16.7 mol% BaO) to R=2.0 (66.7 mol% BaO), where R is the molar ratio of barium oxide to boron oxide. The density, Tg (glass transition temperature), Tx (glass recrystallization temperature), and optical cutoffs were determined. These data were compared with structural models for the glasses based on nuclear

Shalini Kapoor; Henry Bola George; Ashlea Betzen; Mario Affatigato; Steve Feller

2000-01-01

161

Preparation and Characterization of Low-Dielectric Glass Composite with Aluminum Borate  

NASA Astrophysics Data System (ADS)

The effect of aluminum borate ( Al18B4O33) on crystallization and thermal expansion of Pyrex borosilicate glass has been studied. X-ray diffraction (XRD) results show that with 40 vol% aluminum borate, the precipitation of cristobalite in the Pyrex borosilicate glass is completely inhibited. This result is further evidenced by the linear thermal expansion measurement in which, in contrast to the system without aluminum borate, the thermal expansion coefficient remains unchanged with sintering time and is close to that of silicon, 3×10-6 K-1. Moreover, the composite with 40 vol% aluminum borate has a dielectric constant of 5.2 and a dielectric loss of 0.8% at 1 MHz.

Jean, Jau-Ho; Hwang, Shiang-Po

1994-10-01

162

Borate Glass Supports the In Vitro Osteogenic Differentiation of Human Mesenchymal Stem Cells  

Microsoft Academic Search

Bioactive ceramics have the ability to bond to surrounding bone and potentially enhance bone in-growth. Silicate based bioactive glasses and glass-ceramics, such as 45S5 bioactive glass, have been widely investigated for bone repair or as scaffolds for cell-based bone tissue engineering. Recent data have demonstrated that silica-free borate glasses also exhibit bioactive behavior and have been shown to convert to

Nicholas W. Marion; Wen Liang; Gwendolen C. Reilly; Delbert E. Day; Mohamed N. Rahaman; Jeremy J. Mao

2005-01-01

163

Factors affecting optical dispersion in borate glass systems  

NASA Astrophysics Data System (ADS)

Series of ternary glass systems namely, Na2O, B2O3, and RO (R=Ba or Mg) doped with TiO2 are synthesized. The present glasses are dictated by requirement for a small refractive index and a small nonlinear coefficient needed for waveguide and laser fabrication requirements. The effect of MgO and BaO as alkaline earth metals on the optical properties of the glass systems is investigated. The dependence of the refractive index and extinction coefficient dispersion curves on composition is carried out over a wavelength range of 0.3 2.5?m. Applying a genetic algorithm technique, the parameters of Sellmeier dispersion formula that fit index data to accuracy consistent well with the measurements are given. The zero material dispersion-wavelength (ZMDW) and group velocity are also determined using the refractive index data. The Fermi level is calculated exploiting the extinction coefficient dispersion curves. The absorption coefficient, both direct and indirect optical energy gaps, and Urbach energy are evaluated using the absorption edge calculations. The different factors that play a role for controlling the refractive indices such as coordination number, electronic polarizability, field strength of cations, bridging and nonbridging oxygen, and optical basicity are discussed in accordance with the obtained index data. IR spectroscopy is used as a structural probe of the nearest-neighbor environment in the glass network.

Abdel-Baki, Manal; Abdel-Wahab, F. A.; Radi, Amr; El-Diasty, Fouad

2007-08-01

164

A GAMMA-RAY INDUCED ABSORPTION BAND IN SOME LEAD BORATE GLASSES  

Microsoft Academic Search

Observations made on some lead borate, lead aluminoberate, and lead ; beroaluminosilicate glasses showed that an absorption band is induced at 1.5 ev ; (825 m mu ) by gamma irradiation. Experimental evidence indicates that this band ; is associated with Pb\\/sup 2+\\/ ions and beron in the structure of these glasses. ; On replacing PbO by TlâO in a

ADLI M. BISHAY

1960-01-01

165

Rare earth doped tellurite glasses  

NASA Astrophysics Data System (ADS)

Glasses based on TeO2-BaO-MgO-ZnO-Na2O have been made successfully. The Raman scattering and the transmission properties were measured, and the photoluminescence properties of Pr3+ doped tellurite glasses were studied. Tellurite glasses exhibit an IR transmission cut- off beyond approximately 6 micrometers . The maximum-phonon band is at 745 cm-1. The emission from the Pr3+:1G4 yields 3H5 transition is at 1.295 micrometers wavelength with a spectral bandwidth of 30 nm. Pr3+ doped tellurite glasses appear to be a promising candidate for waveguide amplifiers in the 1.3 micrometers telecommunication window.

Man, S. Q.; Liu, H. W.; Pun, Edwin Y.; Chung, Po Sheun

1998-12-01

166

Boson peak of lithium and cesium borate glass studied by Raman scattering  

NASA Astrophysics Data System (ADS)

The composition dependence of boson peaks has been studied by Raman scattering in lithium and cesium borate glass, xM2O-(1-x)B2O3 (M = Li, Cs). The boson peak frequency markedly increases for the increase of the lithium composition, while for the cesium composition the boson peak frequency is nearly constant. It is found that the boson peak frequency clearly correlates with shear modulus. The origin of the boson peak of lithium and cesium borate binary glass is probably the coupled vibration of the libration of boroxol rings and rattling like vibrations of alkali ions. All observed boson peaks of lithium borate glass is scaled by the master curve. It indicates that the distribution of V-DOS remains the same in lithium borate glass. While, the broadening of a boson peak is observed in cesium borate glass. The extension of the distribution of V-DOS is induced probably by the large coordination number of Cs ions inserted in the network structure.

Kojima, S.; Kodama, M.

2011-10-01

167

The effect of titanium oxide on the optical properties of lithium potassium borate glass  

NASA Astrophysics Data System (ADS)

Borate glass is one of the popular hosts that have been widely used in technological applications. In this work, Li2O-K2O-B2O3 (LKB) glasses co-doped with different concentration of titanium oxide (TiO2) have been prepared by chemical quenching technique. The X-ray Diffraction (XRD) results showed the amorphous nature of the sample. Fourier transform infrared (FTIR) spectra, energy band gap, density, ion concentration, molar volume, Polaron radius and inter-nuclear distance and other significant parameters have been analyzed in the light of the different oxidation states of the dopant ions in the glass matrix. Based on the up-conversion phenomenon, the addition of different concentration of TiO2 ions illustrates its effect on the Photoluminescence (PL) emission of LKB. Due to the change in the activator concentration, a broad blue emission with intensity of around 300 (au) has been observed with 0.3 mol% concentration. Enhancement of about three times has been shown with the increment of 0.7 mol% in concentration. The current results are attributed to electron-phonon vibration obtained after the charge transferred from the valence state (O2/2p6) to the conductive state (Ti/3d). The new host showed a non-linear optical relation, that promises to be useful for future optical and electro-optical devices, related to telecommunications, optical storage, and all-optical computing disciplines, particularly for the sample doped with 0.7 mol%.

Alajerami, Yasser Saleh Mustafa; Hashim, Suhairul; Wan Hassan, Wan Muhamad Saridan; Ramli, Ahmad Termizi

2012-10-01

168

Characterization of Special Glasses with Optical Absorption, Thermoluminescence and Electron Spin Resonance.  

National Technical Information Service (NTIS)

Alkaline borate glasses with technological interest were investigated and its characterizations in the borate glasses doped with copper were carried out. Optical absorption, thermoluminescence and electron spin resonance techniques have been used, particu...

E. F. Chinaglia M. L. F. Nascimento S. C. Trippe M. Matsuoka S. Watanabe

1994-01-01

169

Effect of Gamma Irradiation on Alkali Borate Glasses by EPR Spectroscopy  

NASA Astrophysics Data System (ADS)

Alkali borate glasses interesting application in safe nuclear fuel disposal were investigated under gamma irradiation. Glasses with different composition were prepared by conventional melt quench technique. In order to explore the defects created in the glass structure due to gamma irradiation, the EPR spectrum has been taken before and after high dose rate. The results revealed that the signal of involved paramagnetic species after irradiation shown slow time decay. Annealing procedure was performed to recover radiation damage.

Catallo, N.; Baccaro, S.; Colacicchi, S.; Gualtieri, G.; Ferrara, G.; Sharma, G.

2010-04-01

170

Atom probe tomography of lithium-doped network glasses.  

PubMed

Li-doped silicate and borate glasses are electronically insulating, but provide considerable ionic conductivity. Under measurement conditions of laser-assisted atom probe tomography, mobile Li ions are redistributed in response to high electric fields. In consequence, the direct interpretation of measured composition profiles is prevented. It is demonstrated that composition profiles are nevertheless well understood by a complex model taking into account the electronic structure of dielectric materials, ionic mobility and field screening. Quantitative data on band bending and field penetration during measurement are derived which are important in understanding laser-assisted atom probe tomography of dielectric materials. PMID:24713345

Greiwe, Gerd-Hendrik; Balogh, Zoltan; Schmitz, Guido

2014-06-01

171

Heat capacity, glass transition temperature, size of cooperatively rearranging regions, and network connectivity of sodium silicate and alkali borate glasses  

SciTech Connect

The radius of cooperatively rearranging domains at the glass transition in sodium silicate glasses and the number of bridging oxygen atoms in these domains are assessed within the framework of the kinetic theory of thermal fluctuations. The tendencies of the heat capacity, T{sub g}, and the cooperative rearrangement scale with the alkali oxide concentration in sodium silicate and alkali borate glasses are compared. The points of similarity and distinctions between them are revealed.

Borisova, N.V.; Ushakov, V.M.; Shultz, M.M. [Grebenshchikov Institute of Silicate Chemistry, St. Petersburg (Russian Federation)

1994-07-01

172

The preparation and characterization of a lithium borate glass prepared by the gel technique  

NASA Technical Reports Server (NTRS)

The preparation of an amorphous lithium borate gel by the metal organic procedure is described. In addition, a preliminary evaluation of the behavior of the gel upon heating is given. In particular the crystallization tendency of the gel is studied with the aid of DTA and X-ray diffraction, and the structural changes in the gel are monitored with the aid of IR spectroscopy. The glass produced from the lithium borate gel is compared to both the gel precursor material and a glass of similar composition prepared by conventional techniques. Specifically, the relevant water contents, crystallization behavior, and structural features are contrasted.

Weinberg, M. C.; Neilson, G. F.; Smith, G. L.; Dunn, B.; Moore, G. S.; Mackenzie, J. D.

1985-01-01

173

Influence of compositions on sealing temperature and properties of lead borate non-crystallizing sealing glasses  

Microsoft Academic Search

Lead borate sealing glasses, composed of 30–75PbO, 20–65B2O3, 0–10ZnO, 1–5Bi2O3 and 0–4GeO2 in mole percent, were prepared by conventional melting-quenching method. Influence of PbO\\/B2O3 ratios and the content of oxide additives on sealing temperature, thermal expansion properties, thermal stabilities and mechanical properties of lead borate glass were investigated by IR, DSC, thermal expansion and mechanical measurement. Results indicate that the

Yin Cheng; Hanning Xiao; Weiming Guo

2007-01-01

174

Ultrasonic and Thermal Properties of Borate and Phosphate Glasses Containing Bismuth and Lead  

SciTech Connect

Systematic series of (B2O3,P2O5)-Bi2O3-PbO glasses have been successfully prepared by using the rapid quenching technique in which each oxide content changes for every series on the basis of its weight percentage. Their amorphous natures were confirmed earlier by the x-ray diffraction technique. The experimental results show that the density of both glasses, determined by using the Archimedes principle, increases with the glass modifier content. This is due to the replacement of Bi2O3 and PbO in the borate and phosphate glassy networks. The molar volume for borate glass increases with the addition of bismuth and lead oxides, but a reverse trend occurs for the phosphate glass. The longitudinal and shear ultrasound velocities, determined by the MBS 8000 system, of both lead bismuth borate and phosphate glasses show a decreasing trend as more PbO and Bi2O3 are added to the glass system. The increase in PbO/Bi2O3 content was probably related to the progressive increase in the concentration of non-bridging oxygen (NBOs). Thermal studies of the glass, using the Labsys DTA-Setaram machine, show that the value of the glass transition temperature (Tg) is closely related to the chemical bond in the system. In lead bismuth borate glasses, the addition of more Pb2+ and Bi3+ results in a more dominant ionic bond character in the system and hence decreases Tg of the sample. However, in lead bismuth phosphate glasses, the addition of Pb2+ and Bi3+ not only failed to weaken the covalent character in P-O-P bonds, but strengthened it further, leading to an increment in the values of Tg.

Aziz, Sidek Hj. Abd.; Ahmad, Hamezan; Wahab, Zaidan A.; Sulaiman, Zainal Abidin; Talib, Zainal Abidin; Shaari, A. Halim [Glass Research Laboratory, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Senin, H. B. [Department of Physical Sciences, Faculty of Science and Technology, University Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu (Malaysia)

2007-05-09

175

Ion transport mechanism in borate glasses: Influence of network structure on non-Arrhenius conductivity  

NASA Astrophysics Data System (ADS)

In this paper, we report a non-Arrhenius behavior in the temperature-dependent dc conductivity of alkali ion conducting borate glasses below their glass transition. This behavior is strongly influenced by the alkali oxide content and by the type of the alkali ions, and is most pronounced in glasses with low alkali oxide content and with large alkali ions. In contrast to many fast ion conducting glasses, the curvature in the Arrhenius plot is positive. Furthermore, we show that annealing of the glass samples leads to a partial recovery of the Arrhenius behavior. Our experimental results are interpreted in terms of local structural changes in the borate network with temperature, which have been detected by means of solid state NMR spectroscopy.

Murugavel, S.; Roling, B.

2007-11-01

176

Radiation damage of alkali borate glasses for application in safe nuclear waste disposal  

NASA Astrophysics Data System (ADS)

The Electron Paramagnetic Resonance technique has been used to study the time decay of paramagnetic species induced by gamma irradiation and the radiation hardness of different alkali borate glasses for their application in safe nuclear waste disposal. Glasses with different composition have been prepared by conventional melt-quenching. Glass compositions have been chosen to elucidate the role of different alkali cations and of aluminium oxide on the borate glass network. The paramagnetic states detected in these glasses have been attributed, according to the literature, to the formation of hole centers associated with threefold coordinated boron. The results indicate that the time decay trend of the different glasses is slow and that the constant decay does not appear related to the chemical composition. Moreover, the undesired strong fading of the radiation-induced signal during the first 24 h after irradiation, observable in silicate glasses has not been detected. Although no species detectable by a X band spectrometer have been generated, the interaction of lithium borate glasses with air seem to accelerate the system decay rate. Annealing was finally performed and optimized, investigating the correlation between the chemical composition and the radiation damage recovery.

Baccaro, S.; Catallo, N.; Cemmi, A.; Sharma, G.

2011-01-01

177

In vitro evaluation of cytotoxicity of silver-containing borate bioactive glass.  

PubMed

The cytotoxicity of silver-containing borate bioactive glass was evaluated in vitro from the response of osteoblastic and fibroblastic cells in media containing the dissolution products of the glass. Glass frits containing 0-2 weight percent (wt %) Ag were prepared by a conventional melting and quenching process. The amount of Ag dissolved from the glass into a simulated body fluid (SBF), measured using atomic emission spectroscopy, increased rapidly within the first 48 h, but slowed considerably at longer times. Structural and microchemical analysis showed that the formation of a hydroxyapatite-like layer on the glass surface within 14 days of immersion in the SBF. The response of MC3T3-E1 and L929 cells to the dissolution products of the glass was evaluated using SEM observation of cell morphology, and assays of MTT hydrolysis, lactate dehydrogenase release, and alkaline phosphatase activity after incubation for up to 48 h. Cytotoxic effects were found for the borate glass containing 2 wt % Ag, but not for 0.75 and 1 wt % Ag. This borate glass containing up to ?1 wt % Ag could provide a coating material for bacterial inhibition and enhanced bioactivity of orthopaedic implant materials such as titanium. PMID:20878930

Luo, Shi-Hua; Xiao, Wei; Wei, Xiao-Juan; Jia, Wei-Tao; Zhang, Chang-Qing; Huang, Wen-Hai; Jin, Dong-Xu; Rahaman, Mohamed N; Day, Delbert E

2010-11-01

178

Mechanism for converting Al2O3-containing borate glass to hydroxyapatite in aqueous phosphate solution.  

PubMed

The effect of replacing varying amounts (0-2.5 mol.%) of B2O3 with Al2O3 in a borate glass on (1) the conversion of the glass to HA in an aqueous phosphate solution and (2) the compressive strength of the as-formed HA product was investigated. Samples of each glass (10 x 10 x 8 mm) were placed in 0.25 M K2HPO4 solution at 60 degrees C, and the conversion kinetics to HA were determined from the weight loss of the glass and the pH of the solution. The structure and composition of the solid reaction products were characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. While the conversion rate of the glass to HA decreased considerably with increasing Al2O3 content, the microstructure of the HA product became denser and the compressive strength of the HA product increased. The addition of SiO2 to the Al2O3-containing borate glass reversed the deterioration of the conversion rate, and produced a further improvement in the strength of the HA product. The compressive strength of the HA formed from the borate glass with 2.5 mol.% Al2O3 and 5 mol.% SiO2 was 11.1 +/- 0.2 MPa, which is equal to the highest strengths reported for trabecular bone. The results indicated that simultaneous additions of Al2O3 and SiO2 could be used to control the bioactivity of the borate glass and to enhance the mechanical strength of the HA product. Furthermore, the HA product formed from the glass containing both SiO2 and Al2O3 could be applied to bone repair. PMID:19119086

Zhao, Di; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E; Wang, Deping

2009-05-01

179

Evaluation of borate bioactive glass scaffolds with different pore sizes in a rat subcutaneous implantation model.  

PubMed

Borate bioactive glass has been shown to convert faster and more completely to hydroxyapatite and enhance new bone formation in vivo when compared to silicate bioactive glass (such as 45S5 and 13-93 bioactive glass). In this work, the effects of the borate glass microstructure on its conversion to hydroxyapatite (HA) in vitro and its ability to support tissue ingrowth in a rat subcutaneous implantation model were investigated. Bioactive borate glass scaffolds, designated 13-93B3, with a grid-like microstructure and pore widths of 300, 600, and 900?µm were prepared by a robocasting technique. The scaffolds were implanted subcutaneously for 4 weeks in Sprague Dawley rats. Silicate 13-93 glass scaffolds with the same microstructure were used as the control. The conversion of the scaffolds to HA was studied as a function of immersion time in a simulated body fluid. Histology and scanning electron microscopy were used to evaluate conversion of the bioactive glass implants to hydroxyapatite, as well as tissue ingrowth and blood vessel formation in the implants. The pore size of the scaffolds was found to have little effect on tissue infiltration and angiogenesis after the 4-week implantation. PMID:23241965

Deliormanli, Aylin M; Liu, Xin; Rahaman, Mohamed N

2014-01-01

180

Effects of borate-based bioactive glass on neuron viability and neurite extension.  

PubMed

Bioactive glasses have recently been shown to promote regeneration of soft tissues by positively influencing tissue remodeling during wound healing. We were interested to determine whether bioactive glasses have the potential for use in the treatment of peripheral nerve injury. In these experiments, degradable bioactive borate glass was fabricated into rods and microfibers. To study the compatibility with neurons, embryonic chick dorsal root ganglia (DRG) were cultured with different forms of bioactive borate glass. Cell viability was measured with no media exchange (static condition) or routine media exchange (transient condition). Neurite extension was measured within fibrin scaffolds with embedded glass microfibers or aligned rod sheets. Mixed cultures of neurons, glia, and fibroblasts growing in static conditions with glass rods and microfibers resulted in decreased cell viability. However, the percentage of neurons compared with all cell types increased by the end of the culture protocol compared with culture without glass. Furthermore, bioactive glass and fibrin composite scaffolds promoted neurite extension similar to that of control fibrin scaffolds, suggesting that glass does not have a significant detrimental effect on neuronal health. Aligned glass scaffolds guided neurite extension in an oriented manner. Together these findings suggest that bioactive glass can provide alignment to support directed axon growth. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2767-2775, 2014. PMID:24027222

Marquardt, Laura M; Day, Delbert; Sakiyama-Elbert, Shelly E; Harkins, Amy B

2014-08-01

181

ROLE OF CERIUM IN SUPPRESSION OF GAMMA-RAY INDUCED COLORING OF BORATE GLASSES  

Microsoft Academic Search

The role of cerium in the suppression of gamma-ray induced coloration in ; glass was found to depend on the relative concentration of Ce\\/sup 3+\\/ to Ce\\/sup ; 4+\\/ ions as well as on the total cerium content. In a borate glass having high ; ultraviolet transmission, it was found that both Ce\\/sup 3+\\/ and Ce\\/sup 4+\\/ ions ; are

ADLI M. BISHAY

1962-01-01

182

Viscosity and thermal expansion of mixed-alkali sodium-potassium borate glasses  

Microsoft Academic Search

The transformation-range viscosity and thermal expansion behavior of sodium-potassium borate glasses were studied. The results indicate that negative deviations from additivity in the viscosity of these glasses are a function of the NaâO to KâO ratio and that the magnitude of these deviations increases with alkali oxide content. The thermal expansion coefficient exhibits a maximum deviation from additivity as a

CHRISTOPHER M. KUPPINGER; JAMES E. SHELBY

1985-01-01

183

Structure and ion dynamics of silver borate glasses: A 109Ag NMR study  

Microsoft Academic Search

An analysis of the 109Ag isotropic chemical shift ? in the glasses of the AgI:Ag2O:B2O3 system is presented. In these glasses, ? covers a range of ?500 ppm but does not depend linearly upon the fraction of I? anions X=[I]\\/[Ag]. This means that, when AgI is added to the borate network, structures are preferentially formed in which silver is coordinated

Marco Villa; Gaetano Chiodelli; Aldo Magistris; Giovanni Licheri

1986-01-01

184

Ion Exchange in Fused Salts. Iii. The Cation Exchange Characteristics of Some Borate, Borosilicate, and Borophosphate Glasses in Fused Sodium Nitrate.  

National Technical Information Service (NTIS)

Six glasses, comprised of two alkali borates, two salt-loaded alkali borates, one low-silica borosilicate, and one borophosphate, were prepared and tested as ion exchangers for use with fused-salt solvents. These high-alkali borate glasses, including the ...

M. H. Rowell

1966-01-01

185

Composition and temperature dependence of cesium-borate glasses by molecular dynamics.  

PubMed

The structural aspects of xCs2O-(1-x)B2O3 glasses have been investigated by molecular dynamics as functions of Cs2O content (x=0.2, 0.3, and 0.4) and temperature (T=300 and 1250 K). The tetrahedral (BØ4-) and triangular (BØ3,BØ2O-, and BØO2 (2-)) short-range order borate units were found to be the structure-building entities of the simulated glasses [Ø=bridging oxygen (BO) and O-=nonbridging oxygen (NBO) atom]. The increase of Cs2O content results in the progressive increase of the NBO-containing triangle population at the expense of the BO4- tetrahedral units. The same effect is caused by temperature increase at a fixed Cs2O content, and this was associated with the "fragile" characteristics of alkali borate glasses. A comparison of simulated Cs and Li borates showed very similar structures at x=0.2, but dissimilar ones when the alkali content exceeds this composition. In particular, for x>0.2 Cs borates exhibit a preference for NBO formation relative to Li borates. Differences in the microstructure of sites hosting Cs ions were found, and this permits their classification into bridging (b type) and nonbridging type (nb type) of sites. b-type sites consist exclusively of BO atoms, while both BO and NBO atoms participate in nb-type sites. These differences in Cs-site local bonding characteristics were found to be reflected on the Cs-O(site) vibration frequencies. Also, the computed Cs-O vibrational responses for simulated Cs borates were found to compare well with experimental far-infrared spectra. PMID:16035856

Vegiri, Alice; Varsamis, Cristos-Platon E; Kamitsos, Efstratios I

2005-07-01

186

A low silica, barium borate glass–ceramic for use as seals in planar SOFCs  

Microsoft Academic Search

A low silica, barium borate glass–ceramic for use as seals in planar SOFCs containing 64mol%BaO, 3mol%Al2O3 and 3mol%SiO2 was studied. Coefficient of thermal expansion (CTE) between 275–550°C, glass transition temperature (Tg), and dilatometric softening point (Ts) of the parent glass were 11.9×10?6°C?1, 552°C, and 558°C, respectively. Glass–ceramic was produced by devitrification heat treatment at 800°C for 100h. It was found

Nattapol Laorodphan; Prachaya Namwong; Worapong Thiemsorn; Manat Jaimasith; Anucha Wannagon; Torranin Chairuangsri

2009-01-01

187

Structural role of europium ions in lead –borate glasses inferred from spectroscopic and DFT studies  

Microsoft Academic Search

Glasses in the system xEu2O3·(100?x)[3B2O3·PbO] with 0?x?35mol% have been prepared from melt quenching method. Structural changes, as recognized by analyzing band shapes of IR spectra, revealed that Eu2O3 causes a change from the continuous borate network to the continuous lead–borate network, interconnected through Pb–O–B and B–O–B bridges.DFT calculations show that lead atoms occupy three different sites in the proposed model.

S. Rada; M. Culea; M. Neumann; E. Culea

2008-01-01

188

The effect of MgO on the optical properties of lithium sodium borate doped with Cu+ ions  

NASA Astrophysics Data System (ADS)

The current work presented the photoluminescence (PL) properties of a new glass system, which are reported for the first time. Based on the attractive properties of borate glass, a mixture of boric acid (70-x mol %) modified with lithium (20 mol %) and sodium carbonate (10 mol %) was prepared. The current study illustrated the effect of dopant and co-dopant techniques on the lithium sodium borate (LNB). Firstly, 0.1 mol % of copper ions doped with LNB was excited at 610 nm. The emission spectrum showed two prominent peaks in the violet region (403 and 440 nm). Then, we remarked the effect of adding different concentration of MgO on the optical properties of LNB. The results showed the great effect of magnesium oxide on the PL intensities (enhanced more than two times). Moreover, an obvious shifting has been defined toward the blue region (440 ? 475 nm). The up-conversion optical properties were observed in all emission spectra. This enhancement is contributed to the energy transfer from MgO ions to monovalent Cu+ ion. It is well known that magnesium oxide alone generates weak emission intensity, but during this increment the MgO act as an activator (co-doped) for Cu+ ions. Finally, energy band gap, density, ion concentration, molar volume, Polaron radius and inter-nuclear distance all were measured for the current samples. The current samples were subjected to XRD for amorphous confirmation and IR for glass characterization before and after dopants addition. Finally, some of significant physical and optical parameters were also calculated.

Alajerami, Yasser Saleh Mustafa; Hashim, Suhairul; Hassan, Wan Muhamad Saridan Wan; Ramli, Ahmad Termizi; Saleh, Muneer Aziz

2013-04-01

189

Effect of alkali content on AC conductivity of borate glasses containing two transition metals  

NASA Astrophysics Data System (ADS)

Sodium borate glasses containing iron and molybdenum ions with the total concentration of transition ions constant and gradual substitution of sodium oxide (network modifier) by borate oxide (network former) was prepared. Densities, molar volume, DC and AC conductivities are measured. The trends of these properties are attributed to changes in the glass network structure. Their DC and AC conductivity increased with increasing NaO concentration. The increase of AC conductivity of sodium borate glasses is attributed to the chemical composition and the hopping mechanism of conduction. Measurements of the dielectric constant ( ?) and dielectric loss (tan ?) as a function of frequency (50 Hz-100 kHz) and temperature (RT-600 K) indicate that the increase in dielectric constant and loss ( ? and tan ?) values with increasing sodium ion content could be attributed to the assumption that Fe and Mo ions tend to assume network-forming position in the glass compositions studied. The variation of the value of frequency exponent s for all glass samples as the function of temperature at a definite frequency indicates that the value of s decreases with increasing the temperature which agrees with the correlated barrier-hopping (CBH) model.

Kashif, I.; Rahman, Samy A.; Soliman, A. A.; Ibrahim, E. M.; Abdel-Khalek, E. K.; Mostafa, A. G.; Sanad, A. M.

2009-11-01

190

Stability of cement-glass packages containing sodium borate salt generated from pressurized water reactor power plants  

SciTech Connect

A new solidification technique using cement-glass, which is a mixture of sodium silicate and cement, was studied for solidification of sodium borate salt of liquid waste generated from pressurized water reactor plants. When the sodium borate salt was solidified with the cement-glass, the resulting package contained eight times more sodium borate than was found in cement because it did not interact with sodium borate. The leaching ratio of cesium ion from the cement-glass package was one-tenth that of cement. Its low leaching ratio was due to the high cesium adsorption ability of cement-glass. The ratio could be theoretically evaluated by considering the cesium adsorption-desorption equilibrium.

Izumida, T.; Kawamura, F.; Chino, K.; Kikuchi, M.

1987-08-01

191

Reaction of SiC{sub f}/SiC composites with a zinc borate glass  

SciTech Connect

Two different types of SiC{sub f}/SiC composites were successfully joined using a zinc borate glass as a joining agent. The characterization of the joined specimens included XRD, DSC, DTA, SEM-EDS, macroporosimetry, and shear testing measurements. For both composites, the interfaces were continuous and crack-free, and a reaction occurred between the liquid glass and the composite`s surface. The large porosity of the chemical vapor deposited (CVI) composite allowed the glass to infiltrate the sandwich structure, the driving force being gaseous product pressurization and capillary surface forces.

Lemoine, P.; Salvo, M.; Ferrais, M.; Montorsi, M. [Polytechnic di Torino (Italy). Material Science and Chemical Engineering Dept.; Scholz, H. [Joint Research Centre, Ispra (Italy). Inst. for Advanced Materials

1995-06-01

192

Medium-range order in cesium borate glasses probed by double-resonance NMR.  

PubMed

Rotational-echo double-resonance NMR is used to probe the proximity of Cs+ network modifiers to network-forming boron in binary cesium borate glasses. Low- and high-alkali glasses show distinctly different dephasing curves, which indicate preferential association of Cs+ with four-co-ordinate boron ([4]degrees )B) at low-alkali contents only. Different [4]B sites within a given glass appear to be subject to the same 133Cs dipolar field, thus placing constraints on the possible assignments of multiple tetrahedral boron peaks to different types of medium-range order and guiding future structural modeling studies. PMID:15589723

Aguiar, Pedro M; Kroeker, Scott

2005-01-01

193

Nano and micro-indentation studies on lithium borate–barium bismuth niobate glasses  

Microsoft Academic Search

The structure and mechanical properties of multifunctional lithium tetra-borate based glasses and glass–ceramics of the system (100?x) Li2B4O7?x(BaO–Bi2O3–Nb2O5) with x=10, 20 and 30 in molar ratio, have been characterized. Nano- and micro-indentation techniques were employed to evaluate the elastic modulus, hardness and toughness of the as-cast and annealed glasses. These were complemented with detailed structural investigations using X-ray diffraction, microscopy

Kaushik Das; C. Karthik; K. B. R. Varma; U. Ramamurty

2008-01-01

194

Evolution of the spectral characteristics upon annealing of lithium borate glasses containing europium and aluminum  

NASA Astrophysics Data System (ADS)

The spectral and structural characteristics of lithium borate glasses containing europium and aluminum have been investigated upon annealing at different temperatures. It has been found that the spectral characteristics of the studied system change nonmonotonically with an increase in the annealing temperature. After annealing at a temperature of 600°C, the luminescence spectra of the glasses exhibit broad structureless bands that are specific for the amorphous phase containing Eu3+ ions. Then, after annealing at T = 700°C, narrow lines appear in the wavelength ranges 585-595 and 610-620 nm, which correspond to the luminescence of the Eu(BO2)3 and EuAl3(BO3)4 borates. A further increase in the annealing temperature ( T = 800-900°C) leads to the disappearance of europium aluminum borate. In the luminescence spectra of these samples, there are narrow bands in the wavelength range ? = 585-595 nm, which are typical of europium metaborate. Finally, at a temperature of 1050°C, these bands disappear and narrow lines appear again in the wavelength range 610-620 nm, which are characteristic of the EuAl3(BO3)4 borate. Thus, the temperature annealing makes it possible to purposely change the spectral characteristics of the studied system in the wavelength range 590-615 nm.

Shmurak, S. Z.; Kedrov, V. V.; Kiselev, A. P.; Zver'kova, I. I.

2013-02-01

195

Laser texturing of doped borosilicate glasses  

NASA Astrophysics Data System (ADS)

We describe a novel process of laser-assisted fabrication of surface structures on doped oxide glasses with heights reaching 10 - 13% of the glass thickness. This effect manifests itself as a swelling of the irradiated portion of the glass, and occurs in a wide range of glass compositions. The extent of such swelling depends on the glass base composition. Doping with Fe, Ti, Co, Ce, and other transition metals allows for adjusting the absorption of the glass and maximizing the feature size. In the case of bumps grown on borosilicate glasses, we observe reversible glass swelling and the bump height can increase or decrease depending on whether the consecutive laser pulse has higher or lower energy compared with the previous one. To understand the hypothetical mechanism, which includes laser heating of glass, glass melting, and directional flow, we explored density, refractive index, fictive temperature, and phase separation dynamics.

Streltsov, Alexander; Dickinson, James; Grzybowski, Richard; Harvey, Daniel; Logunov, Stephan; Ozturk, Alper; Sutherland, James; Potuzak, Marcel

2010-02-01

196

Effect of SnO addition on optical absorption of bismuth borate glass and photocatalytic property of the crystallized glass  

NASA Astrophysics Data System (ADS)

We have found that an addition of SnO in a bismuth-borate glass, CaO-B2O3-Bi2O3-Al2O3-TiO2, decreases the optical absorption coefficient in the visible region, in which selective crystallization of TiO2 was observed after heat treatment. Since selective crystallization of TiO2 was also attained in the SnO-containing glass, the transparency of TiO2 crystallized glass can be improved independently of selective crystallization of TiO2. We have also demonstrated that the rutile-nanocrystallized glass with SnO addition shows a higher photocatalytic activity than the glass without SnO, indicating that this crystallized glass has a large potential for application as transparent photocatalytic materials.

Masai, Hirokazu; Fujiwara, Takumi; Mori, Hiroshi

2008-04-01

197

Thermal properties of barium-borate glass containing iron in the temperature interval 300 to 700K  

Microsoft Academic Search

The study of thermophysical properties of glasses containing transition metal oxide has received lately more attention. Glasses containing iron oxide were studied by Avogadro et aI. [1 ], Kinser [2], Mackenzie [3] and others [41 . The major objective of this work is to study the effect of composition and temperature on the thermal properties of barium-borate glasses containing different

A. A. El-Sharkawy; A. M. Sanad; I. Kashif; M. I. Kenawy; M. B. Osman

1985-01-01

198

Visible and infrared spectroscopy of Pr3+ and Tm3+ ions in lead borate glasses  

NASA Astrophysics Data System (ADS)

The visible luminescence of Pr3+ and Tm3+ ions in lead borate glasses has been investigated as a function of activator concentration. The Judd-Ofelt analysis and the Inokuti-Hirayama model for energy transfer between activator ions have been applied for investigations of the radiative and non-radiative relaxation of the Pr and Tm excited states. Based on the luminescence decay curve analysis, the concentration quenching of the 1D2 emission of Pr3+ and 1G4 emission of Tm3+ ions has been attributed to cross-relaxation processes. The infrared spectroscopic measurements provide information on structural changes in the borate network initiated by optically active (Pr or Tm) ions. Contrary to the praseodymium ions, the thulium ions play an additional role as a glass-modifier in the PbO-B2O-Al2O3-WO3 composition.

Pisarski, W. A.; Pisarska, J.; Dominiak-Dzik, G.; Ryba-Romanowski, W.

2004-09-01

199

Cation-network interactions in binary alkali metal borate glasses. A far-infrared study  

Microsoft Academic Search

The far-infrared spectra of compositions probing the glass-forming regions of all five binary alkali metal borate systems chi MâO x (1 - chi)BâOâ (0 < chi less than or equal to 0.40, M = Na; and 0 < chi less than or equal to 0.35, M = K, Rb, Cs) have been measured and analyzed to systematically study the alkali

E. I. Kamitsos; M. A. Karakassides; G. D. Chryssikos

1987-01-01

200

Absorption and emission properties of Nd 3+ in lithium cesium mixed alkali borate glasses  

Microsoft Academic Search

Lithium cesium mixed alkali borate glasses of the composition 67B2O3·xLi2O·(32?x)Cs2O (where x=8, 12, 16, 20 and 24) containing 1mol% Nd2O3 were prepared by melt quenching. The absorption spectra of Nd3+ were studied from the experimental oscillator strengths and the Judd–Ofelt intensity parameters were obtained. The intensity parameters are used to determine the radiative decay rates (emission probabilities of transitions) (AT),

Y. C. Ratnakaram; A. Vijaya kumar; D. Tirupathi Naidu; R. P. S. Chakradhar

2005-01-01

201

Absorption and emission properties of Nd3+ in lithium cesium mixed alkali borate glasses  

Microsoft Academic Search

Lithium cesium mixed alkali borate glasses of the composition 67B2O3·xLi2O·(32-x)Cs2O (where x=8, 12, 16, 20 and 24) containing 1 mol% Nd2O3 were prepared by melt quenching. The absorption spectra of Nd3+ were studied from the experimental oscillator strengths and the Judd Ofelt intensity parameters were obtained. The intensity parameters are used to determine the radiative decay rates (emission probabilities of

Y. C. Ratnakaram; A. Vijaya Kumar; D. Tirupathi Naidu; R. P. S. Chakradhar

2005-01-01

202

Spectroscopic properties of Ce 3+ ions in a barium-sodium borate glass  

Microsoft Academic Search

We studied the spectroscopic properties of Ce3+ ions in a borate glass through optical absorption, excitation, time-resolved fluorescence, and excited state absorption (ESA) measurements. The Stark levels of the 5d-state, fluorescence properties of the 5d ? 4f transition, and the nonradiative transition process from the lowest Stark level of the 5d-state are reported. The ESA from the lowest Stark level

J. J. Ju; T. Y. Kwon; S. I. Kim; J. H. Kim; M. Cha; S. I. Yun

1996-01-01

203

Thermal properties of barium titanium borate glasses measured by thermal lens technique  

Microsoft Academic Search

In this paper, thermal lens spectrometry was used to determine the thermal properties of barium titanium borate glasses as a function of the amount of TiO2 in the ratios 8\\/9 and 1\\/1 of BaO–B2O3. The thermal lens technique was shown to be sensitive to the variation of TiO2 and the ratio of BaO\\/B2O3, through thermal diffusivity and conductivity, with different

C. Jacinto; C. A. C. Feitosa; V. R. Mastelaro; T. Catunda

2006-01-01

204

Thermal Stress-Induced Birefringence in Borate Glass Irradiated by Femtosecond Laser Pulses  

Microsoft Academic Search

Thermal stress-induced birefringence in borate glass which has been irradiated by 800-nm femtosecond laser pulses is observed under cross-polarized light. Due to the high temperature and pressure formed in the focal volume, the material at the edge of the micro-modified region is compressed between the expanding region and the unheated one, then stress emerges. Raman spectroscopy is used to investigate

Ye Dai; Bing-Kun Yu; Bo Lu; Jian-Rong Qiu; Xiao-Na Yan; Xiong-Wei Jiang; Cong-Shan Zhu

2005-01-01

205

Gamma-ray attenuation coefficients in bismuth borate glasses  

Microsoft Academic Search

Mass attenuation coefficients of glasses in the system: xBi2O3(1?x)B2O3 (x=0.30, 0.35, 0.40, 0.45 and 0.55) were determined at 356, 662, 1173 and 1332 keV photon energies using a narrow beam transmission method. Appreciable variations were observed in these coefficients due to changes in the chemical composition of glasses. These coefficients were then used to determine effective atomic numbers of glass

Kulwant Singh; Harvinder Singh; Vishal Sharma; Rohila Nathuram; Atul Khanna; Rajesh Kumar; Surjit Singh Bhatti; Hari Singh Sahota

2002-01-01

206

Fourth-harmonic generation of picosecond glass laser pulses with cesium lithium borate crystals  

SciTech Connect

We report the fourth-harmonic generation of 1.5 ps, 1.053 {mu}m glass laser pulses, where group velocity mismatch plays a significant role, at intensities up to 100 GW/cm{sup 2} using newly developed crystal, cesium lithium borate (CsLiB{sub 6}O{sub 10}). Type-I doubler and type-I quadrupler were used in the fourth harmonic generation experimental scheme. Energy conversion efficiencies of 24{percent} and 53{percent} have been achieved for frequency quadrupling and doubling of the fundamental glass laser pulses, respectively. {copyright} {ital 1996 American Institute of Physics.}

Sharma, L.B.; Daido, H.; Kato, Y.; Nakai, S. [Institute of Laser Engineering, Osaka University, 2-6, Yamada-Oka, Suita 565 (Japan)] [Institute of Laser Engineering, Osaka University, 2-6, Yamada-Oka, Suita 565 (Japan); Zhang, T. [Yamanashi University, Faculty of Engineering, 4-3-11 Takeda, Kofu, Yamanashi 400 (Japan)] [Yamanashi University, Faculty of Engineering, 4-3-11 Takeda, Kofu, Yamanashi 400 (Japan); Mori, Y.; Sasaki, T. [Department of Electrical Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565 (Japan)] [Department of Electrical Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565 (Japan)

1996-12-01

207

Ultrasonic study and physical properties of some borate glasses  

Microsoft Academic Search

The structure of the glass system (75?x)B2O3–xBi2O3–25Li2O, where x=5, 10, 15, and 20mol% was investigated by using pulse-echo technique. Elastic properties of the glass system have been calculated together with Poisson’s ratio and Debye temperature from the measured densities as well as longitudinal and shear ultrasonic velocities at room temperature. Ultrasonic velocity measurements were taken at 4MHz. Estimated parameters based

Yasser B Saddeek

2004-01-01

208

Dielectric anomaly in strontium borate–bismuth vanadate glass nanocomposite  

Microsoft Academic Search

Transparent glass nanocomposites in the pseudo binary system (100?x) SrB4O7 (SBO)–x Bi2VO5.5 (BiV) (0?x?70) were prepared by the splat quenching technique. The nano-crystallization of bismuth vanadate (BiV) in 50SBO–50BiV (in mol%) glass composite has been demonstrated. These were characterized for their structural, thermal and dielectric properties. As-quenched composites under study have been confirmed to be amorphous by X-ray powder diffraction

N Syam Prasad; K. B. R Varma; Sidney B Lang

2001-01-01

209

Specific Features of Changes in the Properties of One and Two-Alkali Borate Glasses Containing Water: I. Viscosity, Thermal Expansion, and Kinetics of Structural Relaxation in Binary Alkali Borate Glasses  

Microsoft Academic Search

Alkali borate glasses with different contents of residual water are prepared by varying the synthesis conditions. The temperature dependences of the viscosity and thermal expansion of glasses are obtained. The structural relaxation parameters are calculated from the hysteresis dilatometric curves measured. The water content is determined using the IR absorption spectra in the range of stretching vibrations of hydroxyl groups

Yu. K. Startsev; O. Yu. Golubeva

2002-01-01

210

Fluorescence line narrowing spectroscopy of Sm{sup 2+} and Eu{sup 3+} in sodium borate glasses  

SciTech Connect

A fluorescence line narrowing technique was carried out for sodium borate glasses containing a Sm{sup 2+} ion and its isoelectonic Eu{sup 3+} ion under a pulsed tunable dye laser excitation. In order to obtain site-dependent information, measurements were made by exciting the inhomogeneously broadened {sup 5}{ital D}{sub 0}-{sup 7}{ital F}{sub 0} transition at 10 K. Line-narrowing fluorescence of the {sup 5}{ital D}{sub 0}{r_arrow}{sup 7}{ital F}{sub 1} transition and the temporal changes of the emission lines were investigated as a function of excitation energy, and the dynamics of excited states for both ions were compared with each other. The results indicate that the site-to-site variations of the inhomogeneous broadening of {sup 5}{ital D}{sub 0}{endash}{sup 7}{ital F}{sub 0} transitions are attributed to the apparent difference in local environment between the Sm{sup 2+} and Eu{sup 3+} ions doped in borate glasses with Na{sub 2}O content from 10 to 20 mol{percent}. Also, a decrease in concentration of rare-earth ions causes a more significant effect on Eu{sup 3+} ions than on Sm{sup 2+} ions in the high-excitation-energy range. It is concluded that the difference in the local environment between Sm{sup 2+} and Eu{sup 3+} is mainly ascribable to the difference in the valence and in the ionic radius. {copyright} {ital 1997 American Institute of Physics.}

Fujita, K.; Tanaka, K.; Hirao, K.; Soga, N. [Division of Material Chemistry, Faculty of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-01 (Japan)] [Division of Material Chemistry, Faculty of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-01 (Japan)

1997-01-01

211

Electronic polarizability of the oxide ion and density of binary silicate, borate and phosphate oxide glasses  

NASA Astrophysics Data System (ADS)

A relationship between the polarizability of the oxide ion ?O 2-( no), determined from the refractive index, and the experimental density has been established for binary oxide glasses, such as the systems of silicate, borate and phosphate. Our present conclusions suggest that the ?O 2-( no) values increase with increasing density. The increasing rate of ?O 2-( no) versus density depends strongly on the charge of metals in glasses. For binary glass systems, such as Bi 2O 3-SiO 2, Bi 2O 3-B 2O 3, Sb 2O 3-B 2O 3, Sb 2O 3-P 2O 5 and Bi 2O 3-P 2O 5, the increasing rate of ?O 2-( no) versus density is much larger (an order of magnitude ranging from one to two) than those of binary oxide glasses containing monovalent alkali and divalent metals.

Qi, Ji; Xue, Dongfeng; Ratajczak, Henryk; Ning, Guiling

2004-06-01

212

Electrical conductivity of silver bismuth borate tellurite glasses  

NASA Astrophysics Data System (ADS)

The AC electrical conductivity of (Ag 2O) x (Bi 2O 3) 30 (B 2O 3) 60-x (TeO 2) 10 glass ( x=0, 2, 4, 5, 10, 15 and 20) were measured at different temperatures and frequencies. The results obtained indicated that glasses containing silver<5 mol% have values nearly approximately equal to AC electrical conductivity. A slight decrease was observed with increasing Ag 2O concentration up to 4 mol%. However, the AC electrical conductivity values increase with increasing silver content, i.e. ?5 mol%. The AC electrical conductivity values, increased with increasing frequency and follow the power law, ?AC= A?s. The frequency exponent s was found to be dependent on frequency and temperature. The s values tended to increase to unity as the temperature decreased. Such results suggest that the correlated barrier-hopping (CBH) model is appropriate for explaining the AC electrical conductivity in these glasses. A pronounced increase in the dielectric loss values was observed with increasing silver content. These reflect the effect of Ag + ions charge carriers on the electrical conductivity of such glasses.

Ali, A. A.; Shaaban, M. H.

2008-07-01

213

Kinetics and mechanisms of the conversion of silicate (45S5), borate, and borosilicate glasses to hydroxyapatite in dilute phosphate solutions  

Microsoft Academic Search

Bioactive glasses with controllable conversion rates to hydroxyapatite (HA) may provide a novel class of scaffold materials\\u000a for bone tissue engineering. The objective of the present work was to comprehensively characterize the conversion of a silicate\\u000a bioactive glass (45S5), a borate glass, and two intermediate borosilicate glass compositions to HA in a dilute phosphate solution\\u000a at 37°C. The borate glass

Wenhai Huang; Delbert E. Day; Kanisa Kittiratanapiboon; Mohamed N. Rahaman

2006-01-01

214

Effect of Sm{sub 2}O{sub 3} addition on electrical and optical properties of lithium borate glasses  

SciTech Connect

The electrical and optical property of lithium borate glasses was investigated. It is observed that conductivity decreases while density and refractive index increases with the addition of Sm{sub 2}O{sub 3}. Radiation length of glasses was determined and it is observed that radiation length decreases with the addition of Sm{sub 2}O{sub 3}.

Gedam, R. S.; Ramteke, D. D. [Department of Applied physics, Visvesvaraya National Institute of Technology, Nagpur-440 010 (India)

2012-06-05

215

Polaronic conduction in barium borate glasses containing iron oxide  

Microsoft Academic Search

The conductivity of xFe2O3·(60?x)BaO·40B2O3 glasses can be described using Mott's models for the small polaron hopping and variable-range hopping processes. The change of resistivity and activation energy with composition indicates that the conduction process varies from ionic to polaronic one. The activation energy is the predominant parameter that affects the conductivity with composition. The calculated values of the conductivity parameters

E. Mansour; G. M. El-Damrawi; Y. M. Moustafa; S. Abd El-Maksoud; H. Doweidar

2001-01-01

216

Studies on the effect of Li{sub 2}SO{sub 4} on the structure of lithium borate glasses  

SciTech Connect

Thermal and spectroscopic investigations have been carried out on a number of glasses with a wide range of compositions in the pseudoternary glass system, Li{sub 2}SO{sub 4}-Li{sub 2}O-B{sub 2}O{sub 3}, to understand the role of sulfate ions in modifying the borate glass structure. Both nuclear magnetic resonance (NMR) and infrared (IR) spectroscopic results indicate that four-coordinate boron atoms are retained in the glass structure to a greater extent in sulfate-containing glasses than in pure lithium borate glasses. There seems to be some evidence for the existence of sulfoborate-type units in Raman spectra in the region of 800--960 cm{sup {minus}1}. These conclusions are supported by the observed behavior of glass transition temperatures and molar volumes. The possibility of formation of sulfoborate-type units is discussed from bonding and thermodynamic points of view.

Ganguli, M.; Rao, K.J. [Indian Inst. of Science, Bangalore (India). Solid State and Structural Chemistry Unit] [Indian Inst. of Science, Bangalore (India). Solid State and Structural Chemistry Unit

1999-02-11

217

Decay behavior of Tb3+ green fluorescence in borate glasses  

NASA Astrophysics Data System (ADS)

In 70B2O3-30CaO-xTb2O3 glasses (x = 0.10-20.0 (mole fraction)) prepared by the melt-quenching method, the decay behavior of the green fluorescence due to the 5D4 ? 7F5 transition of Tb3+ ions was investigated by measuring the fluorescence spectra and time-resolved fluorescence spectra and then by analysis using the integrated intensity ratio of fluorescence bands due to the 5D3 ? 7FJ (J = 5, 4, and 3) and 5D4 ? 7FJ (J = 6, 5, 4, 3, 2, 1, and 0) transitions of Tb3+ ions, and the rate equations. In a 70B2O3-30CaO glass with high phonon energy, it was found that the 98.5% of all the excited electrons of Tb3+ ions were relaxed from the 5D3 to 5D4 level due to the multiphonon relaxation (MR) process. In addition, for x > 6.0, the green fluorescence rapidly decayed with increasing x, because the cross-relaxation process, (5D4 ? 7F0) ? 3(7F0 ? 7F6) among the excited Tb3+ ion at 5D4 and its three neighboring Tb3+ ions at 7F6 easily occurred. For x = 6, the cross-relaxation process, (5D3 ? 5D4) ? (7F0 ? 7F6) between Tb3+ ions was fully promoted and the cross-relaxation process, (5D4 ? 7F0) ? 3(7F0 ? 7F6) was repressed, and almost 100% of excited electrons in Tb3+ ions were available for the fluorescence due to the 5D4 ? 7FJ transitions. As a result, it was found that the 70B2O3-30CaO-6Tb2O3 glass had a potential of the green fiber laser.

Wada, Noriyuki; Kojima, Kazuo

2013-09-01

218

Study of lithium borate glasses containing Bi2O3  

NASA Astrophysics Data System (ADS)

The effect of Bi2O3 addition on the properties of 30Li2O:(70-x)B2O3:xBi2O3 (0?x?35 mol %) has been studied. Density and molar volume are increasing with Bi2O3 content. The observed decrease in glass transition temperature and optical band gap has been explained on the basis of increase in non bridging oxygen which is supported by infrared spectroscopy. From the optical transmittance spectra it is observed that the cut off wavelength increases with Bi2O3 content which is related to the structural changes.

Deshpande, A. V.; Raut, V. D.

2014-04-01

219

Optical harmonic transformations in borate glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 compositions  

NASA Astrophysics Data System (ADS)

A series of un-doped borate glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 compositions of high optical quality and chemical purity were obtained from corresponding polycrystalline compounds using standard glass synthesis and technological conditions developed by authors. The optically thermopoled second harmonic generation (SHG) effect in the Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 glasses were investigated and analyzed.

Padlyak, B. V.; Adamiv, V. T.; Burak, Ya. V.; Kolcun, M.

2013-03-01

220

Diluted and non-diluted ferric ions in borate glasses studied by electron paramagnetic resonance  

Microsoft Academic Search

Electron paramagnetic resonance (EPR) spectra of lithium borate glass (1 - x)(0.63B2O3 · 0.37Li2O) · xFe2O3, with x varying from 0.001 to 0.1, were measured at different microwave frequencies and temperatures. For low Fe3+ concentrations (Fe2O3 molar contents from 0.001 to 0.01), X-band EPR spectra, consisting of a gef = 4.3 peak accompanied by a shoulder continuing down to gef

René Berger; Janis Kliava; El-Mostapha Yahiaoui; Jean-Claude Bissey; Paul K. Zinsou; Pierre Béziade

1995-01-01

221

Correlation of ion dynamics with characteristic length scales and network structural units in bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Ion dynamics in lithium bismuth borate conducting glasses have been reported in wide composition and temperature ranges. The activation energy for the dc conduction has been analysed using Anderson-Stuart model and a correlation between the dc conductivity and the doorway radius has been predicted. The characteristic length scales for ion dynamics, such as mean square displacement and spatial extent of sub-diffusive motion of lithium ions have been determined from the ac conductivity and dielectric spectra, respectively. A direct connection between the ion dynamics and the characteristic length scales and the network structural units have been established.

Shaw, A.; Ghosh, A.

2013-09-01

222

Optical absorption and luminescence properties of Nd 3+ in mixed alkali borate glasses—Spectroscopic investigations  

Microsoft Academic Search

Spectroscopic investigations were performed on 67B2O3·xLi2O·(32-x)Na2O and 67B2O3.·xLi2O·(32-x)K2O (where x=8, 12, 16, 20 and 24) glasses containing 1mol% Nd2O3. Covalency was studied as a function of x using Judd-Ofelt intensity parameters that are related to the ligand field symmetry and the degree of bond covalency. Results show that covalency increases when the third component is added to the binary borate

Y. C. Ratnakaram; A. Vijaya kumar; D. Thirupathi Naidu; R. P. S. Chakradhar; K. P. Ramesh

2004-01-01

223

Thermal Stress-Induced Birefringence in Borate Glass Irradiated by Femtosecond Laser Pulses  

NASA Astrophysics Data System (ADS)

Thermal stress-induced birefringence in borate glass which has been irradiated by 800-nm femtosecond laser pulses is observed under cross-polarized light. Due to the high temperature and pressure formed in the focal volume, the material at the edge of the micro-modified region is compressed between the expanding region and the unheated one, then stress emerges. Raman spectroscopy is used to investigate the stress distribution in the micro-modified region and indicates the redistributions of density and refractive index by Raman peak shift. We suggest that this technique can develop waveguide polarizers and Fresnel zone plates in integrated optics.

Dai, Ye; Yu, Bing-Kun; Lu, Bo; Qiu, Jian-Rong; Yan, Xiao-Na; Jiang, Xiong-Wei; Zhu, Cong-Shan

2005-10-01

224

Effects of fast neutron and gamma irradiation on electrical conductivity of some borate glasses  

NASA Astrophysics Data System (ADS)

Electrical conductivity of samples of Li 2O-B 2O 3 binary glass system containing Al 2O 3, PbO, Fe 2O 3, TiO 2 or V 2O 5 was measured at temperatures ranging between 30 and 200 °C before and after irradiation with fast neutrons or ?-rays. Base and Al 2O 3-containing glasses showed an initial rise in conductivity with the increasing temperature, followed by a steep drop, then a more gradual increase. Glass samples containing lead or one of the transition metal oxides showed a linear pattern of electrical conductivity in response to heating. In these glasses activation energy varied depending on the coordination number of the transition metal ion involved. These changes in electrical conductivity in response to temperature are ascribed to changes in the internal structure of the lithium borate glass, which is also affected by the presence of aluminum, lead or transition metals. The effects of exposing the studied glasses to irradiation were attributed to irradiation-induced changes in the configuration of the glass network, including the formation of matrix defects.

Elalaily, N. A.; Mahamed, R. M.

2002-05-01

225

Influence of europium ions on structure and crystallization properties of bismuth-alumino-borate glasses and glass ceramics  

NASA Astrophysics Data System (ADS)

Differential thermal analysis (DTA), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy measurements have been employed to investigate the xEu 2O 3(100 - x)[2Bi 2O 3·B 2O 3·Al 2O 3] glasses and glass ceramics system, with 0 ? x ? 25 mol%. Melting at 1100 °C for 10 min and rapid cooling at room temperature permitted to obtain glass samples. In order to improve the local order and to develop crystalline phases, the glass samples were kept at 580 °C for 24 h. FTIR data suggest that the europium ions play the network modifier role in the studied glasses. These data show that the glass structure consists of BiO 3, BiO 6, BO 3, BO 4 and AlO 4 structural units, and the conversion among these units mainly depends on the Eu 2O 3 content. Density functional theory (DFT) calculations were employed to develop a model for the ternary bismuth-alumino-borate glasses.

Pascuta, Petru; Rada, Simona; Borodi, Gheorghe; Bosca, Maria; Pop, Lidia; Culea, Eugen

2009-04-01

226

Phase separation and dynamical scaling in borate glasses  

NASA Astrophysics Data System (ADS)

Quasibinary B2O3-PbO-(Al2O3) glasses of two different compositions and at several temperatures inside the miscibility gap were investigated using small-angle x-ray scattering. Measurements were carried out using an x-ray beam from a synchrotron source in pinhole collimation and the samples were isothermally annealed in situ. The experimentally determined structure function was found to be in general agreement with recently proposed scaling laws. The exponent for the time dependence of the characteristic scaling length was found to change from a minimum value of 0.24 to a maximum of 0.35 for, respectively, samples near the center and near the boundary of the miscibility gap. The time exponent for the maximum of the structure function was found to be nearly equal to three times the exponent of the characteristic length, as expected from the scaling laws. The scaling structure function changes appreciably with composition, becoming considerably sharper near the boundary of the miscibility gap.

Craievich, A. F.; Sanchez, J. M.; Williams, C. E.

1986-08-01

227

Immobilization of gadolinium in borate-tellurate glasses  

NASA Astrophysics Data System (ADS)

Glasses in the xGd2O3·(100-x)[6TeO2·4B2O3] system, where x = 0, 5, 10, 15, 25 and 30 mol%, have been prepared from melt quenching method. The structural changes were studied by FTIR spectroscopy and DFT calculations. The FTIR spectroscopy data for these systems show that the gadolinium ions have a strong affinity towards the structural units containing non-bridging oxygens, which are negative-charged, because they are readily available for charge compensation. So that, it seems that the content of [BO4] structural units cannot become higher, because the modified [BO3] units containing one or more B-O-Gd bonds are unable to accept a fourth oxygen atom. On the other hand, the gadolinium ions have also an affinity pronounced towards [TeO3] structural units yielding the deformation of the Te-O-Te linkages. The compositional evolution of the network was accommodated with excess of oxygen by the formation of orthoborate structural units, disintegration of some boroxol rings and radical rearrangement of the network formed by the [TeO6] octahedral units.

Rada, S.; Culea, E.; Rada, M.; Maties, V.; Bosca, M.; Pop, L.; Fechete, R.; Chelcea, R.; Moldovan, D.

2009-08-01

228

Raman scattering study of barium borate glasses and melts  

NASA Astrophysics Data System (ADS)

Glasses and melts of xBaO-(100-x)B2O3 (x=20, 25, 30, 35, 40, 45, 50, 55, 60 and 67 mol%) composition have been prepared and studied using high-temperature Raman spectroscopy. It was shown that the structure of the glassy and molten samples with relatively low concentrations of barium oxide (x=20-35 mol%) consists of [B?4]- charged tetrahedra (? is a bridging oxygen atom), B?2O- asymmetric triangles (O- is a non-bridging oxygen atom) and B?3 neutral units. The concentration of [B?4]- tetrahedra (N4) monotonously decreases with increasing BaO content in the melts structure, whereas N4 demonstrates a maximum at x?40 mol% in the glassy samples. B?O22- pyroborate units appear at x?40 mol%, and BO33- orthoborate anions are also formed in the melts structure when x=60 and 67 mol%. The dominant mechanisms for the structural reorganizations generated by changes in temperature depend on the melt composition. The changes in the short range order (SRO) structures can be described by the [B?4]-?B?2O- isomerization reaction at 2550 is most likely described by the 2B?2O?B?O22-+B?3 disproportionation reaction. In both cases, the equilibrium shifts to the right with an increase in temperature. Significant changes in the local structures of melts with a low concentration of barium oxide (x?20 mol%) were not found.

Osipov, Armenak A.; Osipova, Leyla M.

2013-07-01

229

Coordination and ion-ion interactions of chromium centers in alkaline earth zinc borate glasses probed by electron paramagnetic resonance and optical spectroscopy  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance (EPR), optical absorption and FT-IR studies have been carried out on chromium ions incorporated in alkaline earth zinc borate glasses. The EPR spectra exhibit two resonance signals with effective g values at g ? 1.99 and ?1.97. The resonance signal at g ? 1.99 is attributed to the contribution from both the exchange coupled Cr3+-Cr3+ ion pairs and the isolated Cr3+ ions and the resonance signal at g ? 1.97 is due to Cr5+ ions. The paramagnetic susceptibility (?) was calculated from the EPR data at various (123-303 K) temperatures and the Curie temperature (?p) was calculated from the 1/?-T graph. The optical absorption spectra exhibit three bands at ˜360 nm, ˜440 nm and a broad band at ˜615 nm characteristic of Cr3+ ions in an octahedral symmetry. From the observed band positions, the crystal-field splitting parameter Dq and the Racah parameters (B and C) have been evaluated. From the ultraviolet edges, the optical band gap energies (Eopt) and Urbach energy (?E) are calculated. The theoretical optical basicity (?th) of these glasses has also been evaluated. Chromium ions doped alkaline earth zinc borate glasses show BO3 and BO4 structural units in the FT-IR studies.

Sumalatha, B.; Omkaram, I.; Rajavardana Rao, T.; Linga Raju, Ch

2013-05-01

230

Optical properties of cerium doped oxyfluoroborate glass  

NASA Astrophysics Data System (ADS)

Cerium doped oxyfluoroborate glasses have been prepared and its spectroscopic properties have been discussed. It is found that the absorption edge shifts towards the lower energy side for the higher concentration of cerium dopant. Optical band gap for these glasses have been calculated and it is found that the number of non-bridging oxygen increases with cerium content. The emission spectra of these glasses have been recorded using UV laser radiations (266 and 355 nm) and it is observed that these glasses show bright blue emission. On the basis of excitation and emission spectra we have reported the existence of at least two different emission centers of Ce3+ions.

Bahadur, A.; Dwivedi, Y.; Rai, S. B.

2013-06-01

231

Optical properties of cerium doped oxyfluoroborate glass.  

PubMed

Cerium doped oxyfluoroborate glasses have been prepared and its spectroscopic properties have been discussed. It is found that the absorption edge shifts towards the lower energy side for the higher concentration of cerium dopant. Optical band gap for these glasses have been calculated and it is found that the number of non-bridging oxygen increases with cerium content. The emission spectra of these glasses have been recorded using UV laser radiations (266 and 355 nm) and it is observed that these glasses show bright blue emission. On the basis of excitation and emission spectra we have reported the existence of at least two different emission centers of Ce(3+)ions. PMID:23583876

Bahadur, A; Dwivedi, Y; Rai, S B

2013-06-01

232

Gentamicin-Loaded Borate Bioactive Glass Eradicates Osteomyelitis Due to Escherichia coli in a Rabbit Model  

PubMed Central

The treatment of osteomyelitis induced by Gram-negative bacilli is rarely reported in the literature. This study established a rabbit tibia model of osteomyelitis induced by the Gram-negative bacillus Escherichia coli. Using this model, pellets composed of a chitosan-bonded mixture of borate bioactive glass and gentamicin were evaluated in vitro and in vivo for the treatment of osteomyelitis induced by Escherichia coli. Our results showed that the pellets in phosphate-buffered saline released gentamicin continuously over 26 days. Without the simultaneous use of a systemic antibiotic, the implantation of the gentamicin-loaded pellets into the osteomyelitis region of the tibia resulted in the eradication of 81.82% of infections, as determined by microbiological, histological and radiographic evaluation, and supported the ingrowth of new bone into the tibia defects after 6 weeks of implantation. The results indicate that the gentamicin-loaded borate bioactive glass implant, combining sustained drug release with the ability to support new bone formation, could provide a method for treating osteomyelitis induced by Gram-negative bacilli.

Xie, Zongping; Cui, Xu; Zhao, Cunju; Huang, Wenhai; Wang, Jianqiang

2013-01-01

233

In vitro bioactivity, cytocompatibility, and antibiotic release profile of gentamicin sulfate-loaded borate bioactive glass/chitosan composites.  

PubMed

Borate bioactive glass-based composites have been attracting interest recently as an osteoconductive carrier material for local antibiotic delivery. In the present study, composites composed of borate bioactive glass particles bonded with a chitosan matrix were prepared and evaluated in vitro as a carrier for gentamicin sulfate. The bioactivity, degradation, drug release profile, and compressive strength of the composite carrier system were studied as a function of immersion time in phosphate-buffered saline at 37 °C. The cytocompatibility of the gentamicin sulfate-loaded composite carrier was evaluated using assays of cell proliferation and alkaline phosphatase activity of osteogenic MC3T3-E1 cells. Sustained release of gentamicin sulfate occurred over ~28 days in PBS, while the bioactive glass converted continuously to hydroxyapatite. The compressive strength of the composite loaded with gentamicin sulfate decreased from the as-fabricated value of 24 ± 3 MPa to ~8 MPa after immersion for 14 days in PBS. Extracts of the soluble ionic products of the borate glass/chitosan composites enhanced the proliferation and alkaline phosphatase activity of MC3T3-E1 cells. These results indicate that the gentamicin sulfate-loaded composite composed of chitosan-bonded borate bioactive glass particles could be useful clinically as an osteoconductive carrier material for treating bone infection. PMID:23820937

Cui, Xu; Gu, Yifei; Li, Le; Wang, Hui; Xie, Zhongping; Luo, Shihua; Zhou, Nai; Huang, Wenhai; Rahaman, Mohamed N

2013-10-01

234

Silicate and borate glasses as composite fillers: a bioactivity and biocompatibility study.  

PubMed

Composites filled with a silicate glass (CSi) and a new borate glass (CB) were developed and compared in terms of their in vitro behaviour both in acellular and cellular media. Acellular tests were carried out in SBF and the composites were characterized by SEM-EDS, XRD and ICP. Biocompatibility studies were investigated by in vitro cell culture with MG-63 osteoblast-like and human bone marrow cells. The growth of spherical calcium phosphate aggregates was observed in acellular medium on all composite surfaces indicating that these materials became potentially bioactive. The biological assessment resulted in a dissimilar behavior of the composites. The CSi demonstrated an inductive effect on the proliferation of cells. The cells showed a normal morphology and high growth rate when compared to standard culture plates. Contrarily, inhibition of cell proliferation occurred in the CB probably due to its high degradation rate, leading to high B and Mg ionic concentration in the cell culture medium. PMID:21556978

Lopes, P P; Ferreira, B J M Leite; Gomes, P S; Correia, R N; Fernandes, M H; Fernandes, M H V

2011-06-01

235

Optical absorption and fluorescence properties of Er3+/Yb3+ codoped lead bismuth alumina borate glasses  

NASA Astrophysics Data System (ADS)

Lead bismuth alumina borate glasses codoped with Er3+/Yb3+ were prepared by melt quenching technique. Optical absorption, FTIR and photoluminescence spectra of these glasses have been studied. Judd-Ofelt theory has been applied to to the f ? f transitions for evaluating ?2, ?4 and ?6 parameters. Radiative properties like branching ratio ?r and the radiative life time ?R have been determined on the basis of Judd-Ofelt theory. Upconversion emissions have been observed under 980nm laser excitation at room temperature. Green and red up-conversion emissions are centered at 530, 550 and 656 nm corresponding to 2H11/2?4I15/2, 4S3/2?4I15/2 and 4F9/2?4I15/2 transitions of Er3+ respectively. The results obtained are discussed quantitatively based on the energy transfer between Yb3+ and Er3+.

Goud, K. Krishna Murthy; Reddy, M. Chandra Shekhar; Rao, B. Appa

2014-04-01

236

Boson peak in alkaline borate glasses: Raman spectroscopy, neutron scattering, and specific-heat measurements  

NASA Astrophysics Data System (ADS)

The dependence of the boson peak on the alkaline ion in modified borate glasses (M2O)0.14(B2O3)0.86 (M+=Li+,Na+,K+,Cs+) was analyzed by performing Raman spectroscopy, inelastic neutron scattering, and low-temperature specific-heat measurements. It is found that the distribution of vibrations merging into the boson peak shifts to higher frequency by going from cesium to lithium. A linear correlation between the boson peak frequency and the transverse sound velocity is evidenced. The dependence on the polarizing power of the metallic cation is analyzed, stemming from considerations about elastic moduli. These findings suggest a mainly transverse character of the excess vibrational modes in glasses.

D'Angelo, G.; Carini, G.; Crupi, C.; Koza, M.; Tripodo, G.; Vasi, C.

2009-01-01

237

UV-VIS-NIR spectral optical properties of silver iodide borate glasses  

NASA Astrophysics Data System (ADS)

We present a study of optical properties of a series of silver iodide borate glasses(AgI)x(Ag2O·B2O3)1?xby UV-VIS-NIR spectroscopy. The results show an increased absorbance in the whole analysed spectral range when the AgI concentration is augmented. In particular, the enhanced intensity of the wavelength band at 400–500 nm with silver iodine content suggests that this band arises from plasmon-related absorption, describing the formation of silver nanoparticles. With respect to this study, our results could motivate novel target designs consisting of ternary silver boron based bulk glasses for generating resonant absorption of laser light by plasma.

Crupi, C.; Di Marco, G.; Torrisi, L.; Branca, C.; Carini, G.; Wanderlingh, U.; D'Angelo, G.

2014-04-01

238

Experimental and theoretical studies of the structure of tellurate-borate glasses network.  

PubMed

The structural properties of the xTeO(2) x (1-x)B(2)O(3) glasses (x = 0.6; 0.7) were investigated by FT-IR spectroscopy. From the analysis of the FTIR spectra, it is reasonable to assume that by the increasing of boron ions content, the tetrahedral [BO(4)] units are gradually replaced by the trigonal [BO(3)] units. The increase in the number of non-bridging oxygen atoms would decrease the connectivity of the glass network and will yield the depolymerization of the borate chains. The molecular structure and vibrational frequencies of the proposed structural models have been studied by exploring the density functional theory (DFT) calculations. The FTIR spectra of the xTeO(2) x (1-x)B(2)O(3) vitreous systems were compared with the calculated spectrum. This procedure allowed us to assign most of the observed IR bands. PMID:20127395

Rada, Simona; Culea, Eugen; Neumann, Manfred

2010-08-01

239

Effect of fluoride ions on the preparation of transparent glass ceramics based on crystallization of barium borates  

Microsoft Academic Search

Formation of transparent glass-ceramics based on crystallization of barium borate (BBO) crystals from BaO·B2O3 glass-systems, with and without addition of BaF2 has been investigated. Crystallization of glass-samples was done by controlled thermal heat-treatment, at nucleation and crystallization temperatures, for different times and rates. When the glasses were heat-treated at the nucleation temperature, transparent glass-ceramics containing 0.1–0.3?m BBO crystals were prepared.

S. A. M. Abdel-Hameed; N. A. Ghoniem; E. A. Saad; F. H. Margha

2005-01-01

240

Specific Features of Changes in the Properties of One and Two-Alkali Borate Glasses Containing Water: III. Thermal Expansion and the Structural and Mechanical Relaxation Parameters of Two-Alkali Borate Glasses  

Microsoft Academic Search

The thermal expansion and stress relaxation in mixed alkali borate glasses containing lithium, sodium, and potassium oxides with a total alkali oxide content of 15 mol % are measured on an inclined quartz dilatometer and a relaxometer. The experimental data obtained are used to determine the thermal expansion coefficients and the structural and mechanical relaxation parameters. No deviations from the

Yu. K. Startsev; O. Yu. Golubeva

2002-01-01

241

Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC  

SciTech Connect

Complex heat capacity, C{sub p}* = C{sub p}' - iC{sub p}'', of lithium borate glasses Li2O{center_dot}(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent C{sub p}* by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena.

Matsuda, Yu; Ike, Yuji [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571 (Japan); Matsui, Chihiro [College of Engineering Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan); Kodama, Masao [Department of Applied Chemistry, Sojo University, Kumamoto, 860-0082 (Japan); Kojima, Seiji [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571 (Japan); College of Engineering Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan)

2006-05-05

242

Comparisons in Neutron Detection, as modeled by MCNPX, in Li6 Glass, HE3, BF3, and Borated PVT  

Microsoft Academic Search

With the potential shortage of He-3 being reported by venders, it is important to consider other materials for neutron detection. Traditional neutron detectors are composed of BF-3 and He-3. Recently Li-6 Glass and borated PVT have been presented as possible replacements. This work will compare the relative detection efficiencies and consider other factors to determine the most appropriate neutron detection

Lawrence Lakeotes; Craig Marianno

2009-01-01

243

Effect of the sintering temperature on the structural and magnetic parameters of strontium ferrites doped with kaolin and barium borate  

Microsoft Academic Search

This paper presents the results of studies of the effect of the sintering temperature of strontium ferrites (doped with 1.2 mass % kaolin and barium borate) on their properties. The fine crystalline structure of anisotropic and demagnetized strontium ferrites doped with kaolin was studied with the help of the Moessbauer effect. Fe-57 nuclei, occupying 4f2 and 2a octahedral positions, respectively,

V. P. Pashchenko; O. A. Kostyagina; S. M. Lisitsyn; A. K. Prokopenko; L. Y. Selivanova; D. Y. Serebro

1986-01-01

244

Effect of silver nanoparticles on the fluorescence of Pb2+ and compositional dependence of Sm3+ fluorescence in borate glasses  

NASA Astrophysics Data System (ADS)

Borate glasses have been widely studied due to their good optical and mechanical properties. Lead and bismuth (PbO/Bi2O 3:B2O3) borate glasses belong to a family of heavy metal oxide (HMO) glasses which are well known to be chemically durable, stable against atmospheric moisture, have low melting temperatures and good corrosion resistance. The first part of this work deals with lead borate glasses with silver nanoparticles (NPs) introduced into the glass matrix. Transmission electron microscopy characterization is done to verify the nucleation of NPs. Fluorescence and optical absorption experiments are then carried out after different heat treatment duration to investigate the influence of silver NPs on the optical properties of lead (Pb2+) by comparing with a glass sample without silver NPs. Optical absorption experiments show that a well-defined surface plasmon resonance (SPR) peak due to Ag NPs can be observed only for samples that were annealed for 36 hrs. Pb2+ fluorescence spectra reveal that the presence of silver NPs creates new emission centers for Pb2+ ions by altering their chemical environment. The second part of the work involves the use of samarium (a rare earth ion) as a dopant in lead and bismuth borate glasses. The concentration of samarium (Sm3+) is fixed and the base glass composition is varied. The goal is to investigate the compositional dependence of optical properties of samarium in the base glass (PbO/Bi2O3:B 2O3). Optical absorption spectra have been collected and the oscillator strength of each transition - including the hypersensitive - is obtained. The Optical absorption edge is found to shift toward lower energies with increasing PbO/Bi2O3 concentration. Both the oscillator strength and the peak position of the hypersensitive transition show significant variation with glass composition. Strong interaction between Sm3+ ions and Pb2+/Bi3+ ions can also be seen from the variations in the fluorescence emission properties of Sm3+ as a function of base glass composition. Studying the variation of these optical properties will help to create the optimum rare-earth ion-host configuration for possible technological applications. This is the thrust of our future investigations of these glass systems. Keywords: Borate glasses, nanoparticles, fluorescence, transmission electron microscopy, optical absorption, surface plasmon resonance, rare-earth (RE) ions, oscillator strength, hypersensitive transition (HST).

Olumoroti, Akinloluwa T.

245

Physical properties of alkaline-earth and alkali borate glasses prepared over an extended range of compositions  

Microsoft Academic Search

By using rapid cooling we have greatly extended the reported glass-forming ranges in the binary magnesium, calcium, strontium, and barium borate systems. We observed phase separation for low alkaline-earth oxide contents, typically below about 15 mol% alkaline-earth oxide, but we have been able to increase the alkaline-earth oxide limit of glass formation to approximately 60–65 mol%. We have determined the

Nathan P. Lower; Justin L. McRae; Heidi A. Feller; Ashlea R. Betzen; Shalini Kapoor; Mario Affatigato; Steven A. Feller

2001-01-01

246

Ligand field modification around Cu2+ ions in sodium borate glass by codoping.  

PubMed

Understanding the effect of codoping on the properties of photonic glasses is important for improving their properties. The effect of codoping on the ligand field around Cu(2+) ions in a sodium borate glass is examined using optical absorption spectroscopy, continuous-wave electron paramagnetic resonance, and three-pulse electron-spin-echo envelope-modulation. Glass with a composition of 0.1CuO·5Na(2)O·95B(2)O(3) was codoped with 2 mol % of Al(3+), Si(4+), P(5+), Zr(4+), or La(3+) oxide. Three codoping effects are found: strengthening the ligand field, as observed for Zr-codoping, which induces a large blue shift of the optical absorption peak of Cu(2+); weakening the ligand field, as observed for P-codoping, which causes a red shift of the Cu(2+) absorption peak; and almost no effect on the ligand field, which is observed for Al-, Si-, and La-codoping. Coordination structure models based on local charge neutrality are proposed for the codoped glasses. The mechanism of the codoping effect is revealed by elucidating the local structure around Cu(2+). PMID:21526847

Funabiki, Fuji; Matsuishi, Satoru; Hosono, Hideo

2011-05-26

247

Optical Absorption Spectra of Sodium Borate Cobalt Doped Glasses  

SciTech Connect

Glassy system: xNa2O-(100-x-y)B2O3-yCo3O4 has been prepared by conventional melt quenching technique. Optical absorption spectra have been obtained in the range 300 - 2500 nm at room temperature. An absorption edge was observed in the near UV range, the analysis of which reveals that indirect transition is the dominant absorption mechanism. All prepared samples exhibit blue color, indicating that the Co ions are acted upon by tetrahedral ligand field. Obtained spectra were used to estimate some ligand field parameters.

Elokr, M. M.; Hassan, M. A. [Physics Dept. Faculty of Science. Al Azhar University. Cairo (Egypt); Yaseen, A. M. [Physics Dept. Faculty of Education. Ain shams University. Cairo (Egypt); Elokr, R. [National center of Radiation technology. Cairo (Egypt)

2007-02-14

248

The Development of Doped Radiosensitive Glass  

SciTech Connect

For a range of industrial and medical situations there exists need for sensitive, robust high spatial resolution systems for radiation measurements. Our overall focus is on the development of doped silica-glass thermoluminescent dosimeters (TLD) with a view towards improving upon the thermoluminescence (TL) yield of commercially produced optical fibers. In baseline studies of the latter, as detailed herein, measurements have been conducted using Ge-doped communication fibers, employing sources of irradiation including bremsstrahlung x-rays (produced by a nominal accelerating potential of 50 kVp), alpha particles from an 241Am source (predominant emission 5.486 MeV) and protons of energy 2.5 MeV provided by an ion beam source. Present studies, also including elemental analysis via the PIXE and RBS techniques, permit comparison with higher TL yield doped glasses previously made by this group via the sol-gel technique and characterized in part using a range of synchrotron techniques.

Bradley, D. A.; Okoya, O. O. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Hugtenburg, R. P. [School of Physics and Astronomy, University of Birmingham, B15 2TT (United Kingdom); Queen Elizabeth Medical Centre, University Hospital Birmingham NHS Trust, B15 2TH (United Kingdom); Hashim, Suhairul; Ramli, A. T.; Wagiran, H. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Yusoff, A. L. [Department of Nuclear Medicine, Radiotherapy and Oncology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian (Malaysia); Hassan, A. Aziz Mat [Telekom Research and Development Sdn. Bhd., Idea Tower, Incubation Center, UPM-MTDC, Lebuh Silikon, UPM, 43400 Serdang, Selangor Darul Ehsan (Malaysia)

2007-05-09

249

B K-Edge XANES of Superstructural Units in Borate Glasses  

SciTech Connect

The potential of x-ray absorption near-edge structure (XANES) spectroscopy for studying medium range order in borate glasses is assessed by theoretical modelling of the spectra. B K edge XANES is calculated in case that B atoms are located in isolated BO3 and BO4 units and in case that B atom are located in superstructural units of 9-15 atoms. It is found that boroxol ring and diborate and ditriborate superstructural units give rise to spectra which differ from spectra obtained by a mere superposition of spectra of isolated BO3 and BO4 units. On the other hand, spectra of pentaborate and triborate units do not differ significantly from spectra of isolated BO3 and BO4.

Sipr, O.; Simunek, A. [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, CZ-162 53 Prague (Czech Republic); Rocca, F. [IFN-CNR, Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Sezione 'CeFSA' di Trento, Via Sommarive 18, I-38050 Povo (Trento) (Italy)

2007-02-02

250

Thermally activated relaxations and vibrational anharmonicity in alkali-borate glasses: Brillouin scattering study  

NASA Astrophysics Data System (ADS)

Measurements of Brillouin light scattering have been performed in (M2O)0.14(B2O3)0.86 alkali-borate glasses, where M=Li and K, as a function of temperature between 15 and 300 K. The temperature behaviors of hypersonic attenuation and velocity have been explained in terms of thermally activated relaxations of intrinsic structural defects and of anharmonic interactions between hypersonic waves and thermal vibrational modes. In the temperature region above 150 K, where the mean free path of thermal modes is shorter than the acoustic wavelength, it has been shown that the sound propagation is mainly regulated by the Akhiezer mechanism of “phonon viscosity.” It causes a linear increase in the hypersonic attenuation and a linear decrease in the sound velocity with increasing temperature.

Carini, Giovanni, Jr.; Tripodo, Gaspare; Borjesson, Lars

2008-07-01

251

Femtosecond laser induced coordination transformation and migration of ions in sodium borate glasses  

SciTech Connect

We report on the coordination transformation of B{sup 3+} ions and migration of Na{sup +} and O{sup 2-} ions in sodium borate glasses, induced by 250 kHz, 800 nm femtosecond laser irradiation. Micro-Raman spectra show that the ratio of the integrated intensity of the two peaks at 806 and 774 cm{sup -1} decreases at first and then increases with increasing distance from the center of the laser modified zone. Electron dispersive x-ray spectra show that a portion of Na{sup +} and O{sup 2-} ions migrate from the vicinity of focal point after the femtosecond laser irradiation. A possible mechanism is proposed to explain the observed phenomena.

Liu Yin; Zhu Bin; Wang Li; Qiu Jianrong [State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Dai Ye; Ma Hongliang [Department of Physics, Shanghai University, Shanghai 200444 (China)

2008-03-24

252

Combination of platelet-rich plasma with degradable bioactive borate glass for segmental bone defect repair.  

PubMed

Porous scaffold biomaterials may offer a clinical alternative to bone grafts; however, scaffolds alone are typically insufficient to heal large bone defects. Numerous studies have demonstrated that osteoinductive growth factor significantly improves bone repair. In this study, a strategy combining degradable bioactive borate glass (BG) scaffolds with platelet-rich plasma (PRP) was tested. The bone defect was filled with BG alone, BG combined with autologous PRP or left empty. Bone formation was analyzed at 4, 8 and 12 weeks using both histology and radiology. The PRP treated group yielded better bone formation than the pure BG scaffold as determined by both histology and microcomputer tomography after 12 weeks. In conclusion, PRP improved bone healing in a diaphyseal rabbit model on BG. The combination of PRP and BG may be an effective approach to repair critical defects. PMID:21473456

Zhang, Ya-Dong; Wang, Gang; Sun, Yan; Zhang, Chang-Qing

2011-02-01

253

Optical properties of amorphous, erbium-doped yttrium alumino-borate thin films  

NASA Astrophysics Data System (ADS)

In this paper, we report on the optical characterizations of erbium-doped yttrium alumino-borate glassy thin films prepared by the polymeric precursor and sol-gel routes and the spin-coating technique. High quality planar waveguides were produced by a multilayer processing of Y 1-xEr xAl 3(BO 3) 4 compositions with x = 0.02, 0.05, 0.10, 0.30, and 0.50. Their optical properties were investigated using transmission, photoluminescence, and m-lines spectroscopy, whereas high resolution scanning electron microscopy (HR-SEM) was applied to check film thickness and surface homogeneity. The refractive indices determined from transmission and m-lines spectroscopy are in good agreement just like the film thickness measured by HR-SEM and transmission spectroscopy. We observed low propagation losses, together with efficient photoluminescence emission for polymeric precursor thin films, involving low cost and environment friendly reactants.

Maia, L. J. Q.; Fick, J.; Hernandes, A. C.; Mastelaro, V. R.; Ibanez, A.

2012-02-01

254

Polytypic modifications in heavily Tb and Eu doped gadolinium aluminum borate crystals  

NASA Astrophysics Data System (ADS)

The evidence of a new polytypic phase was demonstrated in double doped gadolinium aluminum borate (GAB) crystals grown by the high temperature top seeded solution growth (HTTSSG) method. The structures of the rhombohedral and the new monoclinic phases in the Eu0.02Tb0.12Gd0.86Al3(BO3)4 and Eu0.18Tb0.19Gd0.63Al3(BO3)4 compositions were determined by single crystal and powder X-ray diffraction methods. The monoclinic crystals with different compositions have identical structures with space group C2/c. It was concluded that the starting crystallization temperature was the dominant factor in formation of the rhombohedral and monoclinic phases. The crystals with non-centrosymmetric rhombohedral structure (R32) may possess similar compositions as the previous ones but their starting crystallization temperature was lower.

Beregi, E.; Sajó, I.; Lengyel, K.; Bombicz, P.; Czugler, M.; Földvári, I.

2012-07-01

255

Structure of alkali borate glasses at high pressure: B and Li K-edge inelastic X-ray scattering study.  

PubMed

We report the first in situ boron K-edge inelastic x-ray scattering (IXS) spectra for alkali borate glasses (Li2B4O7) at high pressure up to 30 GPa where pressure-induced coordination transformation from three-coordinated to four-coordinated boron was directly probed. Coordination transformation (reversible upon decompression) begins around 5 GPa and the fraction of four-coordinated boron increases with pressure from about 50% (at 1 atm) to more than 95% (at 30 GPa) with multiple densification mechanisms, evidenced by three distinct pressure ranges for (d[4]B/dP)T. The lithium K-edge IXS spectrum for Li-borate glasses at 5 GPa shows IXS features similar to that at 1 atm, suggesting that the Li environment does not change much with pressure up to 5 GPa. These results provide improved understanding of the structure of low-z glass at high pressure. PMID:17358545

Lee, Sung Keun; Eng, Peter J; Mao, Ho-kwang; Meng, Yue; Shu, Jinfu

2007-03-01

256

Effect of heat treatment and concentration of Mn and Fe on the structure of borate glass  

NASA Astrophysics Data System (ADS)

We have studied the magneto-optic Faraday effect (FE) and electron paramagnetic resonance (EPR) in an aluminum potassium borate glass containing Fe oxides as an impurity in a concentration of 1.5 mass % and Mn impurity in variable concentration from 0 to 1.2 mass %. When manganese oxide is added to the glass composition, the paramagnetic contribution to the Faraday effect increases more slowly than the change in the total concentration of paramagnetic ions, which allows us to hypothesize the appearance of clusters in which the paramagnetic ions are coupled by antiferromagnetic interactions. Formation of clusters upon addition of manganese oxide is confirmed by the change in the nature of the EPR spectra, where we observe a manganese concentration dependence of the distribution of iron atoms with respect to the different positions in the glass matrix. Heat treatment leads to a strong increase in the Faraday effect and a change in the spectral dependences of the Faraday effect and the EPR, which is explained by enlargement of the clusters and appearance of nanoparticles.

Ivanova, O. S.; Petrakovskaya, É. A.; Ivantsov, R. D.; Édel'Man, I. S.; Stepanov, S. A.; Zarubina, T. V.

2006-05-01

257

Influence of modifier oxides on spectroscopic properties of Sm3+ doped lithium fluoroborate glass  

NASA Astrophysics Data System (ADS)

Sm3+ doped lithium fluoro-borate glasses with different modifier oxides (Li2B4O7-BaF2-NaF-MO where M = Mg, Ca, Cd and Pb) and combinations of modifier oxides (Li2B4O7-BaF2-NaF-MgO+CaO, Li2B4O7-BaF2-NaF-CdO+PbO) were prepared by means of melt quenching method. These samples were characterized by XRD, FTIR, optical absorption and fluorescence techniques at room temperature. The XRD profiles of all the glasses confirm their amorphous nature and the FTIR spectra reveal the presence of BO3 and BO4 units along with the strong OH- groups in the glass matrices. The influence of modifier oxides on Judd-Ofelt (J-O) intensity parameters and intensity of the emission lines are reported. Judd-Ofelt theory is used to study the spectral properties and to calculate the radiative transition probabilities (AT), branching ratios (?R), integrated absorption cross sections (?) and radiative lifetimes (?R) for certain spectral transitions. From the emission spectral analysis, emission cross-sections (?P) are calculated for the four emission transitions, 4G5/2 ? 6H5/2, 4G5/2 ? 6H7/2, 4G5/2 ? 6H9/2 and 4G5/2 ? 6H11/2 of Sm3+ ion in different lithium fluoro-borate glasses. Among the four transitions, it is observed that the transition 4G5/2 ? 6H7/2 has higher emission cross-section (?P) in all the glass matrices, except in Mg, Cd and Mg-Ca glass matrices. The non-exponential nature of the luminescence decay curves of 4G5/2 level of Sm3+ doped glass matrices are also reported.

Ratnakaram, Y. C.; Balakrishna, A.; Rajesh, D.; Seshadri, M.

2012-11-01

258

Electrical properties of LiBBaTe glass doped with Nd 2O 3  

NASA Astrophysics Data System (ADS)

The dc and ac electrical conductivity of barium tellurite borate glass doped with Nd 2O 3 in the composition 50 B 2O 3- (20-X) BaO- 20TeO 2 10 LiF or Li 2O where x = 0.5, 1, 1.5 and 2 Nd 2O 3 were measured in the temperature range 303-648 K and in the frequency range 0.1-100 kHz. The dc and ac conductivities values increase, whereas the activation energy of conductivities decreases with increasing Nd 2O 3 content in the glasses containing LiF and by the replacement of LiF by Li 2O the conductivity was found to decrease with addition of Nd 2O 3. The electrical conduction has been observed to be due to small polaron hopping at high temperatures. The frequency dependence of the ac conductivity follows the power law ?AC ( ?) = A ? s. The frequency exponent ( s) values (in the range 0.94 and 0.33) decreases with increasing temperature. The dielectric constant and dielectric loss increased with increasing temperature and decreased with increase in frequency for all glasses studied. In LiF glasses, it is observed that, the values of ? and tan ? are observed to increase with the addition of Nd 2O 3 whereas they decrease in the glasses containing Li 2O. The electrical modulus formalism has been used for studying electrical relaxation behavior in studied glasses. It is for first time that the Nd 2O 3 doped barium tellurite borate glasses have been investigated for dc and ac conductivities and dielectric properties over a wide range of frequency and temperature.

Ali, A. A.; Shaaban, M. H.

2010-12-01

259

Effect of host glass on the optical absorption properties of Nd3+, Sm3+, and Dy3+ in lead borate glasses  

Microsoft Academic Search

The effect of host glass composition on the optical absorption spectra of Nd3+, Sm3+, and Dy3+ in lead borate glasses, with PbO contents varying from 30 to 70 mol %, has been analyzed using Judd-Ofelt theory and the compositional dependence has been determined for the hypersensitive bands. Judd-Ofelt intensity parameters Omegat (t=2,4,6), and the radiative transition probabilities. The variation of

M. B. Saisudha; J. Ramakrishna

1996-01-01

260

Conductivity in alkali doped CoO-B2O3 glasses  

NASA Astrophysics Data System (ADS)

Two series of cobalt-borate glasses doped with Li2O and K2O in single and mixed proportions have been synthesized by melt quenching method and investigated for ac conductivity in the frequency range of 50Hz to 5MHz and temperature range of 310K to 610K. From the measured total conductivity, the pure ac component and its frequency exponent, s were determined. In the single alkali doped glasses, for all the frequencies, the conductivity increased with increase of Li2O up to 0.4 mole fractions and decreased for further increase of Li2O. The temperature dependence of conductivity has been analyzed using Mott's small polaron hopping model and activation energy for ac conduction has been determined. Based on conductivity and activation behaviors, in single alkali glasses, a change over of conduction mechanism predominantly from ionic to electronic has been predicted. In mixed alkali doped glasses, the conductivity passed through minimum and activation energy passed through maximum for second alkali (K2O) content of 0.2 mole fractions. This result revealed the mixed alkali effect to be occurring at 0.2 mole fractions of K2O. The frequency exponent, s, was compared with theoretical models such as Quantum Mechanical Tunneling and Correlated Barrier Hopping models and found them to be inadequate to explain the experimental observations. Time-temperature superposition principle has been verified in both the sets of glasses.

Nagaraja, N.; Sankarappa, T.; Santoshkumar; Sadashivaiah, P. J.; Yenkayya

2009-07-01

261

On the Electron Paramagnetic Resonance Studies in Mixed Alkali Borate Glasses  

NASA Astrophysics Data System (ADS)

Mixed alkali effect in oxide based glasses is one of the current research activity and studies on the behavior of spectroscopic parameters in these systems are quite important to understand the basic nature of this phenomenon. EPR studies of mixed alkali glasses Li2O-K2O-ZnO-B2O3 doped with Fe3+ and Mn2+ were carried out at room temperature. The EPR spectra show typical resonances of d5 system (Fe3+ and Mn2+) in all the measured glass specimens. Evaluated hyperfine constant, number of paramagnetic centers and paramagnetic susceptibility values show deviation from the linearity with the progressive substitution of the Li ion with K in glass network.

Padmaja, G.; Reddy, T. Goverdhan; Kistaiah, P.

2011-10-01

262

Magnetic behavior of erbium-zinc-borate glasses and glass ceramics  

NASA Astrophysics Data System (ADS)

Glasses of the system (ErO)?(BO)?(ZnO) (3 ? x ? 15 mol%) were prepared by conventional melt quenching and subsequently converted to glass ceramics by heat treatment of glass samples at 860 °C for 2 h. The magnetic behaviour of the studied glasses and glass ceramics were investigated using a vibrating sample magnetometer (VSM) and a Faraday-type magnetic balance. Magnetic data show that erbium ions are involved in negative superexchange interactions in all the investigated samples, being antiferromagnetically coupled. For all studied samples the experimental values obtained for the effective magnetic moments are lower than the value corresponding to free Er ions and decrease with the increasing of ErO content. The decrease is more pronounced in heat treated samples than untreated ones.

Borodi, G.; Pascuta, P.; Bosca, M.; Stefan, R.; Tetean, R.; Pop, V.; Radulescu, D.

2013-11-01

263

Bioactive borate glass scaffolds: in vitro and in vivo evaluation for use as a drug delivery system in the treatment of bone infection  

Microsoft Academic Search

The objective of this work was to evaluate borate bioactive glass scaffolds (with a composition in the system Na2O–K2O–MgO–CaO–B2O3–P2O5) as devices for the release of the drug Vancomycin in the treatment of bone infection. A solution of ammonium phosphate,\\u000a with or without dissolved Vancomycin, was used to bond borate glass particles into the shape of pellets. The in vitro degradation

Xin Liu; Zongping Xie; Changqing Zhang; Haobo Pan; Mohamed N. Rahaman; Xin Zhang; Qiang Fu; Wenhai Huang

2010-01-01

264

Rare earth-doped glass microbarcodes  

PubMed Central

The development of ultraminiaturized identification tags has applications in fields ranging from advanced biotechnology to security. This paper describes micrometer-sized glass barcodes containing a pattern of different fluorescent materials that are easily identified by using a UV lamp and an optical microscope. A model DNA hybridization assay using these “microbarcodes” is described. Rare earth-doped glasses were chosen because of their narrow emission bands, high quantum efficiencies, noninterference with common fluorescent labels, and inertness to most organic and aqueous solvents. These properties and the large number (>1 million) of possible combinations of these microbarcodes make them attractive for use in multiplexed bioassays and general encoding.

Dejneka, Matthew J.; Streltsov, Alexander; Pal, Santona; Frutos, Anthony G.; Powell, Christy L.; Yost, Kevin; Yuen, Po Ki; Muller, Uwe; Lahiri, Joydeep

2003-01-01

265

Preparation and properties of scintillating glass doped with organic activators  

Microsoft Academic Search

A series of scintillating glasses were developed by doping organic activators into low melting temperature glasses according to different ratios. The fluorescence spectra and the transmission spectra of some scintillating glasses were explored and the actual concentration organic in scintillating glass was estimated. The results show that it is feasible to prepare the scintillating glass by doing organic scintillating activators

Dong-mei ZHU; Fa LUO; Hong-sheng ZHAO; Wan-cheng ZHOU

2006-01-01

266

Molecular dynamics investigation of lithium borate glasses: Local structure and ion dynamics  

NASA Astrophysics Data System (ADS)

The effect of alkali content and temperature on the microstructure of lithium borate glasses, xLi2O-(1-x)B2O3, has been investigated for glass compositions x=0.2-0.5 and temperatures up to 1250 K. The molecular dynamics technique has been applied, with Ewald summation and periodic boundary conditions, to a collection of ca. 256 particles confined in a primitive cubic cell and interacting through a Born-Mayer-Huggins-type potential augmented with three-body angular terms. The short-range order (SRO) structure was found to consist of boron-oxygen tetrahedral, BØ-4 [Ø=bridging oxygen atom (BO)], and triangular units with variable number of nonbridging oxygen (NBO) atoms, BØ3, BØ2O-, and BØO2-2 (O-=NBO). The relative abundance of SRO units was determined and found to depend on both glass composition and temperature. Increasing Li2O content at constant temperature or increasing temperature at a fixed composition was shown to cause rearrangements of the SRO structure and to lead towards BØO2-2 units in the range of compositions and temperatures investigated. Such changes were expressed in terms of chemical equilibria involving the SRO units. The local environments hosting the Li ions were investigated and distinguished in two main types: the first type of site is formed by BO's, while the second type involves the participation of NBO's. The vibrational response of Li ions in the two types of site was computed and found to correlate very well with the experimental far-infrared profiles. Calculation of diffusion coefficients of Li ions showed that diffusion is carried out predominantly through NBO sites. In addition, glass regions rich in Li/NBO were found to develop with increasing lithium oxide content and to percolate eventually into microchannels suitable for ion migration.

Varsamis, Cristos-Platon E.; Vegiri, Alice; Kamitsos, Efstratios I.

2002-03-01

267

Effect of the sintering temperature on the structural and magnetic parameters of strontium ferrites doped with kaolin and barium borate  

SciTech Connect

This paper presents the results of studies of the effect of the sintering temperature of strontium ferrites (doped with 1.2 mass % kaolin and barium borate) on their properties. The fine crystalline structure of anisotropic and demagnetized strontium ferrites doped with kaolin was studied with the help of the Moessbauer effect. Fe-57 nuclei, occupying 4f2 and 2a octahedral positions, respectively, in the hexagonal and spinel blocks, have the highest magnetic fields and quadrupole shifts. The effect of the sintering temperature on the physical properties of the ferrites studied is linked to changes in the microstructure and porosity of the samples.

Pashchenko, V.P.; Kostyagina, O.A.; Lisitsyn, S.M.; Prokopenko, A.K.; Selivanova, L.Y.; Serebro, D.Y.

1986-01-01

268

Bone regeneration in rat calvarial defects implanted with fibrous scaffolds composed of a mixture of silicate and borate bioactive glasses.  

PubMed

Previous studies have evaluated the capacity of porous scaffolds composed of a single bioactive glass to regenerate bone. In the present study, scaffolds composed of a mixture of two different bioactive glasses (silicate 13-93 and borate 13-93B3) were created and evaluated for their response to osteogenic MLO-A5 cells in vitro and their capacity to regenerate bone in rat calvarial defects in vivo. The scaffolds, which have similar microstructures (porosity=58-67%) and contain 0, 25, 50 and 100 wt.% 13-93B3 glass, were fabricated by thermally bonding randomly oriented short fibers. The silicate 13-93 scaffolds showed a better capacity to support cell proliferation and alkaline phosphatase activity than the scaffolds containing borate 13-93B3 fibers. The amount of new bone formed in the defects implanted with the 13-93 scaffolds at 12 weeks was 31%, compared to values of 25, 17 and 20%, respectively, for the scaffolds containing 25, 50 and 100% 13-93B3 glass. The amount of new bone formed in the 13-93 scaffolds was significantly higher than in the scaffolds containing 50 and 100% 13-93B3 glass. While the 13-93 fibers were only partially converted to hydroxyapatite at 12 weeks, the 13-93B3 fibers were fully converted and formed a tubular morphology. Scaffolds composed of an optimized mixture of silicate and borate bioactive glasses could provide the requisite architecture to guide bone regeneration combined with a controllable degradation rate that could be beneficial for bone and tissue healing. PMID:23827095

Gu, Yifei; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E

2013-11-01

269

Physical and structural properties of Nd3+ doped BaO-ZnO-B2O3 glasses  

NASA Astrophysics Data System (ADS)

Nd3+ doped Barium-Zinc-Borate glasses with composition xNd2O3-(100-x)[0.1BaO-0.4ZnO-0.5B2O3]x = 0,0.5,1.0,1.5,2.0 have been prepared by melt-quenching method. X-Ray Diffractogram of the synthesized glass samples confirms the amorphous nature. The physical properties i.e. density and molar volume have been measured and both increases with increase in Nd3+ content. Glass transition temperature have been measured using DSC and found to be increase with Nd3+ content shows good thermal stability. Analysis of FTIR spectra estimate the presence of tetrahedral coordination of Zn (i.e. ZnO4) in synthesized glasses. The basic structural units [BO3] and [BO4] are observed in glasses under study.

Nanda, Kirti; Kundu, R. S.; Punia, R.; Parmar, R.; Kishore, N.

2013-06-01

270

Photoinduced refractive-index changes in several Eu3+-, Pr3+-, and Er3+-doped oxide glasses  

NASA Astrophysics Data System (ADS)

We have observed permanent and transient refractive-index grating formation following excitation of the 5D2 state of Eu3+ in a silicate, a metaphosphate and a pentaphosphate glass at 300 K, using four-wave mixing (FWM). These refractive-index changes recently have been ascribed to a high-energy phonon-mediated structure rearrangement involving two-level systems. In order to test this model, these measurements were extended to several Er3+- and Pr3+-doped glasses, which both have transitions that create similar energy phonons. The 4I11/2 state of an Er3+-doped silicate and a metaphosphate glass was resonantly excited at 980 nm. No permanent gratings were observed in these Er3+ glasses. A single, resonant-pump-beam experiment showed only transient thermal lensing in the Er3+-silicate glass. This is consistent with the FWM results of this glass. Similarly no permanent refractive-index gratings were observed following excitation of the 3P0 state in Pr3+-doped sodium silicate, metaphosphate, and lanthanum and aluminum borate glasses. The Er3+ and Pr3+ results are inconsistent with the two-level-system model and its analysis of the difference in polarizability between the two potential wells as applied to the Eu3+ glasses.

Broer, M. M.; Bruce, A. J.; Grodkiewicz, W. H.

1992-04-01

271

Defect formation of gamma irradiated MoO3-doped borophosphate glasses.  

PubMed

Borophosphate glasses of the basic composition (50P2O5, 30B2O3, 20Na2O mol%) containing different doping molybdenum oxide percents (0.16-0.98) were prepared by melting and annealing method. Infrared and UV-visible absorption spectroscopic measurements before and after gamma irradiation were carried out. The base undoped borophosphate glass reveals strong UV absorption bands but with no visible bands and these UV bands are related to unavoidable trace iron impurities contaminated within the raw materials used for the preparation of this glass. The introduction of MoO3 (in doping ratio) into this glass produces an additional UV band and a broad visible band and their intensities increase with the MoO3 content. These additional bands are related to both Mo(6+) and Mo(5+) ions. The base undoped borophosphate glass shows retardation effect towards gamma irradiation. Gamma irradiation produces marked changes in the UV-visible spectra of Mo-O3-doped glasses. Such changes can be related to the production of induced defects from photochemical reactions and the generation of positive holes. Infrared absorption spectrum of the undoped borophosphate glass reveals complex vibrational bands due to the presence of both phosphate groups beside borate groups with triangular and tetrahedrally coordinated units. The introduction of MoO3 causes some limited variations in the FTIR spectra. Gamma irradiation produces minor changes in the intensities of some IR bands. Such changes are related to the changes in the bond angles and/or bond lengths of few structural groups upon irradiation while the main structural groups remain unchanged in their number and position. PMID:23800775

Abdelghany, A M; Ouis, M A; Azooz, M A; Ellbatal, H A

2013-10-01

272

Defect formation of gamma irradiated MoO3-doped borophosphate glasses  

NASA Astrophysics Data System (ADS)

Borophosphate glasses of the basic composition (50P2O5, 30B2O3, 20Na2O mol%) containing different doping molybdenum oxide percents (0.16-0.98) were prepared by melting and annealing method. Infrared and UV-visible absorption spectroscopic measurements before and after gamma irradiation were carried out. The base undoped borophosphate glass reveals strong UV absorption bands but with no visible bands and these UV bands are related to unavoidable trace iron impurities contaminated within the raw materials used for the preparation of this glass. The introduction of MoO3 (in doping ratio) into this glass produces an additional UV band and a broad visible band and their intensities increase with the MoO3 content. These additional bands are related to both Mo6+ and Mo5+ ions. The base undoped borophosphate glass shows retardation effect towards gamma irradiation. Gamma irradiation produces marked changes in the UV-visible spectra of Mosbnd O3-doped glasses. Such changes can be related to the production of induced defects from photochemical reactions and the generation of positive holes. Infrared absorption spectrum of the undoped borophosphate glass reveals complex vibrational bands due to the presence of both phosphate groups beside borate groups with triangular and tetrahedrally coordinated units. The introduction of MoO3 causes some limited variations in the FTIR spectra. Gamma irradiation produces minor changes in the intensities of some IR bands. Such changes are related to the changes in the bond angles and/or bond lengths of few structural groups upon irradiation while the main structural groups remain unchanged in their number and position.

Abdelghany, A. M.; Ouis, M. A.; Azooz, M. A.; EllBatal, H. A.

2013-10-01

273

Characterization of the glass-to-vitroceramic transition in yttrium aluminum borate laser glasses using solid state NMR.  

PubMed

The crystallization of laser glasses in the system (Y(2)O(3))(0.2){((Al(2)O(3))(x))(B(2)O(3))(0.8-x)} (0.15 ? x ? 0.40) doped with 0.5 mol% of ytterbium oxide has been investigated by x-ray powder diffraction, and various solid state NMR techniques. The crystallization process has been analyzed in a quantitative fashion by high-resolution solid state (11)B, (27)Al, and (89)Y NMR spectroscopy as well as (11)B{(27)Al} and (27)Al{(11)B} rotational echo double resonance (REDOR) experiments. The homogeneous glasses undergo major phase segregation processes resulting in crystalline Al(5)BO(9) (historically denoted as Al(18)B(4)O(33)), YBO(3), crystalline YAl(3)(BO(3))(4), residual glassy B(2)O(3), and an additional yet not identified crystalline phase ("X-phase"). PMID:22244244

Deters, Heinz; Eckert, Hellmut

2012-02-01

274

The effect of V 2O 5 on alkaline earth zinc borate glasses studied by EPR and optical absorption  

NASA Astrophysics Data System (ADS)

10 wt% SrO:30 wt% ZnO:60 wt% B 2O 3 incorporated with different vanadyl concentrations were studied by means of electron paramagnetic resonance (EPR) and optical absorption techniques. The spin-Hamiltonian parameters ( g and A), bonding parameters ( ?2 and ?2?2) and Fermi contact interaction parameter K have been calculated. The values of spin-Hamiltonian parameters indicate that the VO 2+ ions in strontium zinc borate glasses were present in octahedral sites with tetragonal compression. The spin concentration ( N) participating in resonance was calculated as a function of temperature (93-273 K) for strontium zinc borate glass sample containing 0.9 wt% of VO 2+ ions and the activation energy ( Ea) was calculated. From the EPR data, the paramagnetic susceptibility ( ?) was calculated at various temperatures and the Curie constant ( C) was evaluated from the 1/ ?- T graph. The optical absorption spectra of VO 2+ ions in these glasses show two bands corresponding to the transitions 2B 2g ? 2B 1g and 2B 2g ? 2E g in the order of decreasing energy respectively. The optical band gap energies ( Eopt) and Urbach energy (? E) have been determined from their ultraviolet edges. The theoretical values of optical basicity ( ?th) of these glasses have also been evaluated.

Sumalatha, B.; Omkaram, I.; Rajavardhana Rao, T.; Linga Raju, Ch.

2011-12-01

275

Non-bridging oxygens in borate glasses: characterization by 11B and 17O MAS and 3QMAS NMR.  

PubMed

The concentrations of non-bridging oxygens (NBO) in oxide glasses has major effects on their properties and on those of their precursor glass melts. In borate and borosilicate glasses, the presence of NBO bonded to boron has generally been inferred from 11B NMR spectra and mass balance considerations. Here we report the direct observation of such NBO using 17O MAS and 3QMAS techniques, and compare estimates of their populations with those derived from high-resolution 11B MAS spectra. For the latter, two independent methods are used, based on the ratios of trigonal to tetrahedral boron and on the concentrations of trigonal boron sites with large quadrupolar asymmetry parameters. We include data on crystalline sodium pyroborate (Na4B2O5) and sodium metaborate (NaBO2), and several sodium and barium borate glasses. 17O chemical shifts and quadrupolar coupling constants for NBO bonded to boron vary considerably depending on their coordination environment. In borosilicates, peaks for this species may be hidden by overlap with B-O-Si or Si-O-Si resonances. PMID:10811425

Stebbins, J F; Zhao, P; Kroeker, S

2000-05-01

276

IR luminescence in bismuth-doped germanate glasses and fibres  

SciTech Connect

We have studied the optical properties of lightly bismuth doped ({<=}0.002 mol %) germanate glasses prepared in an alumina crucible. The glasses are shown to contain bismuth-related active centres that have been identified previously only in bismuth-doped fibres produced by MCVD. With increasing bismuth concentration in the glasses, their luminescence spectra change markedly, which is attributable to interaction between individual bismuth centres. (optical fibres)

Pynenkov, A A; Firstov, Sergei V; Panov, A A; Firstova, E G; Nishchev, K N; Bufetov, Igor' A; Dianov, Evgenii M

2013-02-28

277

Comparative study of lead borate and bismuth lead borate glass systems as gamma-radiation shielding materials  

Microsoft Academic Search

Gamma-ray mass attenuation coefficients have been measured experimentally and calculated theoretically for PbO–B2O3 and Bi2O3–PbO–B2O3 glass systems using narrow beam transmission method. These values have been used to calculate half value layer (HVL) parameter. These parameters have also been calculated theoretically for some standard radiation shielding concretes at same energies. Effect of replacing lead by bismuth has been analyzed in

Narveer Singh; Kanwar Jit Singh; Kulwant Singh; Harvinder Singh

2004-01-01

278

Structure of Alkali Borate Glasses at High Pressure: B and Li K-Edge Inelastic X-Ray Scattering Study  

SciTech Connect

We report the first in situ boron K-edge inelastic x-ray scattering (IXS) spectra for alkali borate glasses (Li{sub 2}B{sub 4}O{sub 7}) at high pressure up to 30 GPa where pressure-induced coordination transformation from three-coordinated to four-coordinated boron was directly probed. Coordination transformation (reversible upon decompression) begins around 5 GPa and the fraction of four-coordinated boron increases with pressure from about 50% (at 1 atm) to more than 95% (at 30 GPa) with multiple densification mechanisms, evidenced by three distinct pressure ranges for (d{sup [4]}B/dP){sub T}. The lithium K-edge IXS spectrum for Li-borate glasses at 5 GPa shows IXS features similar to that at 1 atm, suggesting that the Li environment does not change much with pressure up to 5 GPa. These results provide improved understanding of the structure of low-z glass at high pressure.

Lee, Sung Keun; Eng, Peter J.; Mao, Ho-kwang; Meng, Yue; Shu, Jinfu (SNU); (CIW); (UC)

2008-06-16

279

Molecular dynamics investigation of mixed-alkali borate glasses: Short-range order structure and alkali-ion environments  

NASA Astrophysics Data System (ADS)

Structural properties of mixed-alkali borate glasses, 0.3[(1-x)Li2O-xCs2O]-0.7B2O3 and 0.3[(1-x)Li2O-xNa2O]-0.7B2O3 , have been studied by molecular dynamics simulations at T=300K and for several values of the alkali mixing parameter, x , to explore structural foundations of the mixed-alkali effect (MAE). The short-range order (SRO) structure was found to consist of borate tetrahedra, B?4- , and of neutral, B?3 , and charged, B?2O- , triangular units [ ?=bridging oxygen atom]. The abundance of B?4- units was found to decrease from Li to Cs and to exhibit negative deviation from linearity in Li-Cs glasses. However, no appreciable change in SRO structure was detected in mixed Li-Na glasses. Even though alkali metal (M) ions occupy in mixed glasses sites, i.e., coordination environments with O atoms, similar to those formed in single alkali borates, mixing was found to affect the M-O bonding properties of dissimilar alkalis in an opposite manner. Thus, for both systems investigated here the Li ion-coordination environment was found to become better defined and the Li-O interactions to strengthen upon alkali mixing, whereas the Cs-O and Na-O interactions become progressively weakened. The origin of these trends was traced to cationic environments formed around nonbridging oxygen (NBO) atoms in glass; it was found that the dominant cation configurations around NBOs consist of dissimilar cations in mixed-alkali glasses. The formation of dissimilar ion pairs affects by polarization effects the bonding and vibrational properties of metal ions in their oxide sites. This was demonstrated for Li-Cs glasses by both experimental and calculated far infrared spectra, where the metal ion-oxide site vibrations are strongly active. It was discussed that the preference of unlike-alkali ion pairing around NBOs and the consequent drastic reduction in the number of NBOs that sense like-cations could provide a structural explanation for the MAE.

Vegiri, A.; Varsamis, C.-P. E.; Kamitsos, E. I.

2009-11-01

280

The role of V 2O 5 in the modification of structural, optical and electrical properties of vanadium barium borate glasses  

Microsoft Academic Search

Vanadium barium borate glasses were prepared by a normal melt quench technique. The infrared spectra of these V2O5·BaO·B2O3 glasses were recorded over a continuous spectral range (400–4000cm?1) in an attempt to study their structure systematically. The conversion from three- to four-fold coordinated boron took place. The fundamental absorption edge for all the glasses was analyzed in terms of the theory

S. Sindhu; S. Sanghi; A. Agarwal; Sonam; V. P. Seth; N. Kishore

2005-01-01

281

Sm3+ doped lithium aluminoborate glasses for orange coloured visible laser host material  

NASA Astrophysics Data System (ADS)

Samarium doped lithium aluminium borate glasses have been prepared by conventional melt quench technique and their detailed spectroscopic analysis has been done. The structural analysis has been done by using FTIR studies and density is measured by Archimedes method. The UV-vis-NIR absorption spectra show an increase in intensity of different transitions from the ground level 6H5/2 to various 2S+1LJ levels with an increase in samarium concentration at the expense of aluminium. The fluorescence spectra show several transitions from 4G5/2 to various 6HJ levels along with 4F3/2 to 6HJ and 4G7/2 to 6H5/2.

Kaur, Parvinder; Kaur, Simranpreet; Singh, Gurinder Pal; Singh, D. P.

2013-10-01

282

Dependence of third-order nonlinear optical effect on refractive index in barium (Li) aluminum (Ga or Si) borate ternary glasses produced by new pulling down technique  

NASA Astrophysics Data System (ADS)

Ternary glasses of barium (Li-substituted) aluminum (Ga- or Si-substituted) borate were solidified by new technique using conventional Floating-zone Pulling Down system. It was difficult to grow single crystalline materials in this system. However, solidification of glasses was easy. Refractive indexes of these glasses were 1.5-1.7. Third-order nonlinear optical effects, ?(3), were larger than that of standard SiO 2 glass at 355 nm. Despite small refractive indexes as oxide glasses, large ?(3) were obtained.

Kimura, H.; Miyazaki, A.; Kannan, C. V.; Cheng, Z. X.

2007-09-01

283

Improved terbium-doped, lithium-loaded glass scintillator fibers  

Microsoft Academic Search

An improved terbium-doped, 6Li-loaded glass scintillator has been drawn into fibers. Tests indicate that the neutron detection response of the fibers is superior to the response with fibers drawn from the original terbium-doped glass. The new fibers offer less attenuation (1\\/e length of ~ 40 cm) and improved gamma ray\\/neutron discrimination. The improved fibers will be incorporated in a scintillator

Garry B. Spector; Tom McCollum; Alexander R. Spowart

1993-01-01

284

Aluminophosphate-doped glasses with rare-earth ions  

Microsoft Academic Search

Aluminophosphate glasses doped with rare-earth ions have recently attracted a large interest owing to their relevant non-linear optical properties. Until now, all studies were done over the glasses doped with rare-earth ions, in which the rare-earth ions were into a vitreous silica matrix. Our study was made as for rare-earth ions into a vitreous aluminophosphate matrix. In the first step,

Rodica Rogojan; Paul E. Sterian; Mihai Elisa

2000-01-01

285

The preparation and characterization of a lithium borate glass prepared by the gel technique  

Microsoft Academic Search

The preparation of an amorphous lithium borate gel by the metal organic procedure is described. In addition, a preliminary evaluation of the behaviour of the gel upon heating is given. In particular the crystallization tendency of the gel is studied with the aid of DTA and X-ray diffraction, and the structural changes in the gel are monitored with the aid

M. C. Weinberg; G. F. Neilson; G. L. Smith; B. Dunn; G. S. Moore; J. D. Mackenzie

1985-01-01

286

Structural models for yttrium aluminium borate laser glasses: NMR and EPR studies of the system (Y2O3)(0.2)-(Al2O3)x-(B2O3)(0.8-x).  

PubMed

The structure of laser glasses in the system (Y(2)O(3))(0.2){(Al(2)O(3))(x))(B(2)O(3))(0.8-x)} (0.15 ? x ? 0.40) has been investigated by means of (11)B, (27)Al, and (89)Y solid state NMR as well as electron spin echo envelope modulation (ESEEM) of Yb-doped samples. The latter technique has been applied for the first time to an aluminoborate glass system. (11)B magic-angle spinning (MAS)-NMR spectra reveal that, while the majority of the boron atoms are three-coordinated over the entire composition region, the fraction of three-coordinated boron atoms increases significantly with increasing x. Charge balance considerations as well as (11)B NMR lineshape analyses suggest that the dominant borate species are predominantly singly charged metaborate (BO(2/2)O(-)), doubly charged pyroborate (BO(1/2)(O(-))(2)), and (at x = 0.40) triply charged orthoborate groups. As x increases along this series, the average anionic charge per trigonal borate group increases from 1.38 to 2.91. (27)Al MAS-NMR spectra show that the alumina species are present in the coordination states four, five and six, and the fraction of four-coordinated Al increases markedly with increasing x. All of the Al coordination states are in intimate contact with both the three- and the four-coordinate boron species and vice versa, as indicated by (11)B/(27)Al rotational echo double resonance (REDOR) data. These results are consistent with the formation of a homogeneous, non-segregated glass structure. (89)Y solid state NMR spectra show a significant chemical shift trend, reflecting that the second coordination sphere becomes increasingly "aluminate-like" with increasing x. This conclusion is supported by electron spin echo envelope modulation (ESEEM) data of Yb-doped glasses, which indicate that both borate and aluminate species participate in the medium range structure of the rare-earth ions, consistent with a random spatial distribution of the glass components. PMID:21814672

Deters, Heinz; de Lima, José F; Magon, Claudio J; de Camargo, Andrea S S; Eckert, Hellmut

2011-09-21

287

Study on borate glass system containing with Bi 2O 3 and BaO for gamma-rays shielding materials: Comparison with PbO  

Microsoft Academic Search

In this work, the mass attenuation coefficients and shielding parameters of borate glass matrices containing with Bi2O3 and BaO have been investigated at 662keV, and compare with PbO in same glass structure. The theoretical values were calculated by WinXCom software and compare with experiential data. The results found that the mass attenuation coefficients were increased with increasing of Bi2O3, BaO

J. Kaewkhao; A. Pokaipisit; P. Limsuwan

2010-01-01

288

Effect of pyrophosphate ions on the conversion of calcium-lithium-borate glass to hydroxyapatite in aqueous phosphate solution.  

PubMed

The conversion of glass to a hydroxyapatite (HA) material in an aqueous phosphate solution is used as an indication of the bioactive potential of the glass, as well as a low temperature route for preparing biologically useful materials. In this work, the effect of varying concentrations of pyrophosphate ions in the phosphate solution on the conversion of a calcium-lithium-borate glass to HA was investigated. Particles of the glass (150-355 ?m) were immersed for up to 28 days in 0.25 M K(2)HPO(4) solution containing 0-0.1 M K(4)P(2)O(7). The kinetics of degradation of the glass particles and their conversion to HA were monitored by measuring the weight loss of the particles and the ionic concentration of the solution. The structure and composition of the conversion products were analyzed using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. For K(4)P(2)O(7) concentrations of up to 0.01 M, the glass particles converted to HA, but the time for complete conversion increased from 2 days (no K(4)P(2)O(7)) to 10 days (0.01 M K(4)P(2)O(7)). When the K(4)P(2)O(7) concentration was increased to 0.1 M, the product consisted of an amorphous calcium phosphate material, which eventually crystallized to a pyrophosphate product (predominantly K(2)CaP(2)O(7) and Ca(2)P(2)O(7)). The consequences of the results for the formation of HA materials and devices by the glass conversion route are discussed. PMID:20680413

Fu, Hailuo; Rahaman, Mohamed N; Day, Delbert E; Huang, Wenhai

2010-10-01

289

Effect of pyrophosphate ions on the conversion of calcium-lithium-borate glass to hydroxyapatite in aqueous phosphate solution  

PubMed Central

The conversion of glass to a hydroxyapatite (HA) material in an aqueous phosphate solution is used as an indication of the bioactive potential of the glass, as well as a low temperature route for preparing biologically useful materials. In this work, the effect of varying concentrations of pyrophosphate ions in the phosphate solution on the conversion of a calcium–lithium–borate glass to HA was investigated. Particles of the glass (150–355 µm) were immersed for up to 28 days in 0.25 M K2HPO4 solution containing 0–0.1 M K4P2O7. The kinetics of degradation of the glass particles and their conversion to HA were monitored by measuring the weight loss of the particles and the ionic concentration of the solution. The structure and composition of the conversion products were analyzed using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. For K4P2O7 concentrations of up to 0.01 M, the glass particles converted to HA, but the time for complete conversion increased from 2 days (no K4P2O7) to 10 days (0.01 M K4P2O7). When the K4P2O7 concentration was increased to 0.1 M, the product consisted of an amorphous calcium phosphate material, which eventually crystallized to a pyrophosphate product (predominantly K2CaP2O7 and Ca2P2O7). The consequences of the results for the formation of HA materials and devices by the glass conversion route are discussed.

Fu, Hailuo; Day, Delbert E.; Huang, Wenhai

2010-01-01

290

Optical properties of rare earth doped transparent oxyfluoride glass ceramics  

NASA Astrophysics Data System (ADS)

Optical properties of Eu3+ ions in oxyfluoride glasses and glass ceramics doped with low concentration (0.1 mol%) have been analysed and compared with previous results for high concentrated samples (2.5 mol%). The Eu3+ ions in the low dopant concentration glass ceramics are diluted into like crystalline environments with higher symmetry and lower coupled phonons energy than in the precursor glasses. Fluorescence line narrowing measurements indicate the presence of two main fluoride site distributions for the Eu3+ ions in these low concentrated glass ceramics.

Mendez-Ramos, J.; Lavin, V.; Martin, I. R.; Rodriguez-Mendoza, U. R.; Rodriguez, V. D.; Lozano-Gorrin, A. D.; Nunez, P.

2003-01-01

291

Effect of zinc-borate glass addition on the thermal properties of the cordierite/Al2O3 composites containing nano-sized spinel crystal.  

PubMed

Low-melting zinc-borate glass was added to the cordierite/Al2O3 composite in order to improve the sintering facility of Al2O3 and formation of nano-sized spinel crystal of high thermal conductivity. Increasing the ZnO/B2O3 ratio in the zinc-borate glass increased the ZnAl2O4 spinel and decreased the Al4B2O9 crystal peak intensities in X-ray diffraction pattern. The XRD peak intensities of the ZnAl2O4 spinel and Al4B2O9 crystals in the specimen containing 10 wt% zinc-borate glass (10G series) are higher than that of the specimen containing 5 wt% zinc-borate glass (5G series). The microstructures of most 10G series specimens had the flower-shaped crystal which was composed of 50 nm wide and 250 nm long needle-like crystals and identified as ZnAl2O4 spinel phase. The thermal conductivity of the 10G series specimen was higher than that of the 5G series in any ZnO/B2O3 ratio due to the formation of plenty of nano-sized ZnAl2O4 spinel of high thermal conductivity. Particularly, the thermal conductivity of the cordierite/Al2O3 composite containing 10 wt% zinc-borate glass of ZnO/B2O3 weight ratio = 1.5 was 3.8 W/Km which is much higher than that of the published value (3.0 W/Km). PMID:24245313

Jo, Sinae; Kang, Seunggu

2013-11-01

292

Effect of SiO2 and Al2O3 addition on the density, Tg and CTE of mixed alkali - alkaline earth borate glass  

NASA Astrophysics Data System (ADS)

Mixed alkali — alkaline earth borate glasses, with the addition of silica and alumina, have been studied for their density, Tg and CTE with a view of exploring the applicability of these glasses in glass to metal sealing applications. It has been observed that silica addition results in an increase in density and Tg while the alumina addition decreases the density and Tg. The variation in CTE exhibits minima with the addition of both, silica and alumina. An attempt is made here to explain the observed variations in the properties on the basis of different mass of the additives, number of non bridging oxygens (NBOs) and other changes in the glass network.

Deshpande, A. M.; Deshpande, V. K.

2009-07-01

293

Exceptionally narrow homogeneous linewidth in erbium-doped glasses  

Microsoft Academic Search

We show that rare-earth (RE-) doped glasses can have homogeneous linewidths as narrow as 287 kHz at 4He temperatures. This is far narrower than others reported in glasses in the same temperature range and is suitable for precise spectral hole burning and spatial-spectral holographic applications. It is known that cw spectral hole burning linewidth measurements of RE ions in glasses

Y. Sun; R. L. Cone; L. Bigot; B. Jacquier

2006-01-01

294

Erbium partitioning in a heavily doped transparent glass ceramic.  

PubMed

An erbium-doped transparent glass ceramic, consisting of LaF3 nanocrystallites with a characteristic length of approximately 20 nm embedded in an aluminosilicate glass matrix and exhibiting infrared-to-green up-conversion, has been studied. The degree of erbium partitioning into the nanocrystallite phase was found using energy transfer coefficients determined from bulk Er3+:LaF3 samples. This transparent glass ceramic sample was found to have a partitioning fraction of 19 +/- 5%. PMID:16127930

Jones, Gina C; Houde-Walter, S N

2005-08-15

295

Study on borate glass system containing with Bi 2O 3 and BaO for gamma-rays shielding materials: Comparison with PbO  

NASA Astrophysics Data System (ADS)

In this work, the mass attenuation coefficients and shielding parameters of borate glass matrices containing with Bi 2O 3 and BaO have been investigated at 662 keV, and compare with PbO in same glass structure. The theoretical values were calculated by WinXCom software and compare with experiential data. The results found that the mass attenuation coefficients were increased with increasing of Bi 2O 3, BaO and PbO concentration, due to increase photoelectric absorption of all glass samples. However, Compton scattering gives dominant contribution to the total mass attenuation coefficients for studied glass samples. Moreover the half value layers (HVL) of glass samples were also better than ordinary concretes and commercial window glass. These results reflecting that the Bi-based glass can use replace Pb in radiation shielding glass. In the case of Ba, may be can use at appropriate energy such as X-rays or lower.

Kaewkhao, J.; Pokaipisit, A.; Limsuwan, P.

2010-04-01

296

Optical and infrared absorption spectra of 3d transition metal ions-doped sodium borophosphate glasses and effect of gamma irradiation.  

PubMed

Undoped and transition metals (3d TM) doped sodium borophosphate glasses were prepared. UV-visible absorption spectra were measured in the region 200-900nm before and after gamma irradiation. Experimental optical data indicate that the undoped sodium borophosphate glass reveals before irradiation strong and broad UV absorption and no visible bands could be identified. Such UV absorption is related to the presence of unavoidable trace iron impurities within the raw materials used for preparation of this base borophosphate glass. The TMs-doped glasses show absorption bands within the UV and/or visible regions which are characteristic to each respective TM ion in addition to the UV absorption observed from the host base glass. Infrared absorption spectra of the undoped and TMs-doped glasses reveal complex FTIR consisting of extended characteristic vibrational bands which are specific for phosphate groups as a main constituent but with the sharing of some vibrations due to the borate groups. This criterion was investigated and approved using DAT (deconvolution analysis technique). The effects of different TMs ions on the FTIR spectra are very limited due to the low doping level (0.2%) introduced in the glass composition. Gamma irradiation causes minor effect on the FTIR spectra specifically the decrease of intensities of some bands. Such behavior is related to the change of bond angles and/or bond lengths of some structural building units upon gamma irradiation. PMID:22995547

Abdelghany, A M; ElBatal, F H; Azooz, M A; Ouis, M A; ElBatal, H A

2012-12-01

297

Spectral investigations of Cu2+ doped beta-barium borate nanopowder by the co-precipitation method  

NASA Astrophysics Data System (ADS)

A Cu2+ doped beta-barium borate nanopowder has been synthesized using the co-precipitation method. The average crystallite size of the present system is evaluated at 68 nm and the lattice cell parameters are calculated from x-ray diffraction data. Optical absorption spectral data reveal that the Cu2+ ions are in a tetragonally distorted octahedral site in the host lattice. Direct, indirect and Urbach energies are calculated with the absorption edge technique. Electron paramagnetic resonance results confirm that the Cu2+ ions enter a tetragonally elongated octahedral site at room temperature. The crystal field and spin-Hamiltonian parameters are also evaluated. Fourier transform infrared spectroscopy confirms the vibrational bands of Ba-O and B-O in the system.

Venkata Reddy, Ch; Rama Krishna, Ch; Udayachandran Thampy, U. S.; Reddy, Y. P.; Rao, P. S.; Ravikumar, R. V. S. S. N.

2011-08-01

298

Luminescent solar concentrators using uranyl-doped silicate glasses  

NASA Astrophysics Data System (ADS)

The effect of the uranium concentration on the performance of uranyl-doped glass used in solar concentrators was examined experimentally. Na-Ca silicate glass and UO3 additive were prepared at 1250 C, cooled to 600 C, annealed at 700 C, and cooled to ambient for the tests. Light absorption was proportional to uranium content up to a 2 percent concentration. A doped-glass test cell filled with a fluoresceine solution and irradiated at 337 nm and 420 nm with laser light was monitored to measure the luminescent lifetimes of the uranyl ions. A 380 microsec half-lifetime was determined, along with a quantum yield that varied from 0.5 at 1 percent uranyl concentration to 0.3 at a 5 percent concentration. The quantum efficiencies could be attained with 1 cm thick glass with existing manufacturing technologies, and thinner glass with further developments.

Folcher, G.; Keller, N.; Paris, J.

1984-09-01

299

Luminescence and spectral hole burning of Sm(2+) doped in Li(2)O-SrO-B(2)O(3) glass-ceramics.  

PubMed

The Sm(3+)-doped alkali strontium borate glass-ceramics were obtained by heating of the as-made glasses in air, where Sm(3+) ions were reduced to Sm(2+) ions. The XRD, optical absorption spectra and luminescence of Sm(3+) and Sm(2+) ions were investigated. The excitation spectra of the (7)F(0)-->(5)D(0) transition were measured in the region of (7)F(0)-->(5)D(1) transition, where spectral holes were burnt within two of the Stark split (5)D(1) bands. The Sm(2+) ions doped glass ceramics exhibit the persistent spectral hole burning at room temperature. The hole depth, which are burned by the DCM dye laser, are about 40% of the total intensity, respectively. It is concluded that the dominant burning mechanism is a photoionization of electron trapping at a site other than Sm(3+) ions because of the absence of an antihole around the burned hole. PMID:19058997

Jiang, Chuanfang; Huang, Yanlin; Park, Seongtae; Jang, Kiwan; Seo, Hyo Jin

2009-03-01

300

Luminescence and spectral hole burning of Sm 2+ doped in Li 2O-SrO-B 2O 3 glass-ceramics  

NASA Astrophysics Data System (ADS)

The Sm 3+-doped alkali strontium borate glass-ceramics were obtained by heating of the as-made glasses in air, where Sm 3+ ions were reduced to Sm 2+ ions. The XRD, optical absorption spectra and luminescence of Sm 3+ and Sm 2+ ions were investigated. The excitation spectra of the 7F 0 ? 5D 0 transition were measured in the region of 7F 0 ? 5D 1 transition, where spectral holes were burnt within two of the Stark split 5D 1 bands. The Sm 2+ ions doped glass ceramics exhibit the persistent spectral hole burning at room temperature. The hole depth, which are burned by the DCM dye laser, are about 40% of the total intensity, respectively. It is concluded that the dominant burning mechanism is a photoionization of electron trapping at a site other than Sm 3+ ions because of the absence of an antihole around the burned hole.

Jiang, Chuanfang; Huang, Yanlin; Park, Seongtae; Jang, Kiwan; Seo, Hyo Jin

2009-03-01

301

Probing and modeling of pressure-induced coordination transformation in borate glasses: Inelastic x-ray scattering study at high pressure  

SciTech Connect

Here, we report on the in situ synchrotron inelastic x-ray scattering spectra of Na-borate glasses at high pressure up to 25 GPa. The pressure-induced boron coordination transformation from {sup [3]}B to {sup [4]}B is linear with pressure characterized by a single value of ({partial_derivative}{sup [3]}B/{partial_derivative}P){sub T}. Previous studies of Li-borate and pure-borate glasses show a nonlinear transformation with multiple ({partial_derivative}{sup [3]}B/{partial_derivative}P){sub T} values for different pressure ranges, revealing the important role cation field strength plays in densification and pressure-induced structural changes. Considering the distribution of the energy difference beween low- and high-pressure states ({Delta}{var_epsilon}) in the energy landscape and the variance of the ratio {Delta}{var_epsilon} to its pressure gradient ({partial_derivative}{Delta}{var_epsilon}/{partial_derivative}P){sub T} as a measure of network flexibility with pressure, an amorphous system with a large variance in {Delta}{var_epsilon} at 1 atm and/or a small ({partial_derivative}{Delta}{var_epsilon}/{partial_derivative}P){sub T} may undergo a gradual coordination transformation (e.g., Na borates). In contrast, a system with the opposite behavior (e.g., Li borates) undergoes an abrupt coordination transformation. The results and concepts of this study thus can shed light on opportunities to study the effect of composition on the nature of densification in low-z oxide and other archetypal glasses and melts.

Lee, Sung Keun; Eng, Peter J.; Mao, Ho-kwang; Shu, Jinfu (SNU); (CIW); (UC)

2009-01-15

302

Line patterning of (Sr,Ba)Nb 2O 6 crystals in borate glasses by transition metal atom heat processing  

Microsoft Academic Search

Some NiO-doped Bi2O3,La2O3–SrO–BaO–Nb2O5–B2O3 glasses giving the formation of strontium barium niobate Sr0.5Ba0.5Nb2O6 (SBN) crystals with a tetragonal tungsten–bronze structure through conventional crystallization in an electric furnace have been developed, and SBN crystal lines have been patterned on the glass surface by heat-assisted (250–300°C) laser irradiation and scanning of continuous-wave Nd:YAG laser (wavelength: 1064nm). The surface morphology and the quality of

M. Sato; T. Honma; Y. Benino; T. Komatsu

2007-01-01

303

Photoluminescence properties of Tb3+-doped heavy scintillating germanate glasses  

Microsoft Academic Search

A group of of heavy germanate glasses containing BaO and\\/or Gd2O3, La2O3, SnO and doped with the scintillating rare earth Tb3+ are presented. Photoluminescence measurements are made on these glasses. The intensity of emission peaks is found proportional to the contents of Tb3+ dopants as well as of Gd3+: the former indicates that no obvious concentration quenching effect is visualized

Guorong Chen; S. Baccaro; A. Cecilia; Shan Wang; Jiaxiang Nie; Yonghui Zhang; Yongjuan Du

2003-01-01

304

Effect of irradiation on differential thermal properties and crystallization behavior of some lithium borate glasses  

NASA Astrophysics Data System (ADS)

Differential thermal properties and the crystallization behavior of binary system Li 2O-B 2O 3 glasses were investigated. The effects of the presence of oxides of aluminum, lead or one of the transition metals TiO 2 or V 2O 5 or Fe 2O 3 in the parent glass were also studied. The effects of three different heat treatments on the crystalline structure of all the studied glasses were also investigated. The results showed that all glass samples were amorphous before the heat treatment, with the most common formed phase being tetraborate Li 2B 8O 13 (Li 2O-4B 2O 3). The exposure of the glass samples to either gamma rays or fast neutrons resulted in considerable changes in their thermal behavior. The results also showed that Tg increases for all studied glasses when subjected to irradiation either by fast neutron or gamma rays, while Tc decreased only at higher doses.

El-Alaily, N. A.; Mohamed, R. M.

2001-07-01

305

Structural, dielectric and optical properties of lithium borate-bismuth tungstate glass-ceramics  

SciTech Connect

Glasses in the system (1 {minus} x)Li{sub 2}B{sub 4}O{sub 7}-xBi{sub 2}WO{sub 6} (0.1 {le} x {le} 0.35) were prepared by spat quenching technique. Powder X-ray diffraction (XRD) and differential thermal analysis (DTA) were employed to characterize the as-quenched glasses. High-resolution transmission electron microscopy (HR-TEM) revealed the presence of fine, nearly spherical crystallites of Bi{sub 2}WO{sub 6} varying from 1.5 to 20 nm in size, depending on x in the as-quenched glasses. The glasses (corresponding to x = 0.3) heat-treated at 723 K for 6 h gave rise to a clear crystalline phase of Bi{sub 2}WO{sub 6} embedded in the Li{sub 2}B{sub 4}O{sub 7} glass matrix, as observed by X-ray studies. The dielectric constants of the as-quenched glasses as well as the glass-ceramics decreased with increase in frequency (40Hz--100 kHz) at 300 K, and the value obtained for the glass-ceramic (x = 0.2) is in agreement with the values predicted using Maxwell's model and the logarithmic mixture rule. The dielectric constants for both the as-quenched glass and the glass-ceramic increased with increase in temperature (300--873 K) and exhibited anomalies close to the onset of the crystallization temperature of the host glass matrix. The optical transmission properties of these glass-ceramics were found to be compositional dependant.

Murugan, G.S.; Varma, K.B.R.

1999-12-01

306

Structural and thermal properties of some zinc borate glasses containing gadolinium ions  

Microsoft Academic Search

Glasses in the system (Gd2O3)x·(B2O3)(60?x)·(ZnO)40 (0 ? × ? 15 mol%) have been prepared by the melt-quenching technique. The local structure and the thermal behaviour of the\\u000a obtained glasses were investigated using X-ray diffraction (XRD), differential thermal analysis (DTA) and Fourier transform\\u000a infrared (FTIR) spectroscopy. The XRD pattern of the glasses confirmed their amorphous nature. Compositional dependence of\\u000a the glass transition (Tg), fragility index (F),

Petru Pascuta; Eugen Culea

2011-01-01

307

Structural relaxation kinetics of antimony borate glasses with covalent bonding character  

Microsoft Academic Search

The structural relaxation kinetics in the glass transition for xSb2O3.(100-x)B2O3 glasses with covalent bonding character has been examined from viscosity and heat capacity measurements. These binary glasses have low glass transition temperatures, Tg=250-290 °C, but show a high thermal resistance against crystallization. The degree of fragility m estimated from the activation energy for viscous flow (E?=290-531 kJ mol-1) is m=29-51.

T. Honma; Y. Benino; T. Komatsu; R. Sato; V. Dimitrov

2001-01-01

308

White light generation from Dy3+ doped tellurite glass  

NASA Astrophysics Data System (ADS)

This paper reports on the spectral results of Dy3+ (1.0 mol%) ions-doped TeO2-ZnO-PbO-PbF2-Na2O (TZPPN) glass. Raman spectrum measurements, differential thermal analysis (DTA) profiles of this rare-earth ion-doped glass were carried out. From the DTA thermogram, glass transition (Tg), crystallization (Tc) and melting (Tm) temperatures were evaluated. Direct and indirect optical band gaps were calculated based on the glasses UV absorption spectra. From the absorption spectra, Judd-Ofelt (J-O) intensity parameters, ?k, were calculated. Using J-O intensity parameters, several radiative properties such as spontaneous transition probabilities (AR), radiative branching ratios (?R) and radiative lifetimes (?R) were determined for the excitation level 4F9/2. From the emission spectra, a strong yellow emission at 574 nm (4F9/2?6H13/2) was observed and it also showed a combination of blue and red emission bands for this glass. The stimulated emission cross-section ?(?p) was also evaluated for the 4F9/2?6HJ (J=11/2, 13/2, and 15/2) transitions. This study indicates that 1 mol% Dy2O3-doped tellurite glass can be considered for white light generation with the excitation of blue light (454 nm).

Damak, Kamel; Yousef, El Sayed; Rüssel, Christian; Maâlej, Ramzi

2014-02-01

309

Flame retardancy mechanisms of aluminium phosphinate in combination with melamine polyphosphate and zinc borate in glass-fibre reinforced polyamide 6,6  

Microsoft Academic Search

The fire retardancy mechanisms of aluminium diethylphosphinate in combination with melamine polyphosphate and zinc borate was analysed in glass-fibre reinforced polyamide 6,6. The influence of phosphorus compounds on the polyamide decomposition pathways was characterized using thermal analysis (TG), evolved gas analysis (TG–FTIR), and FTIR–ATR analysis of the residue. The Lewis acid–base interactions between the flame retardants, the amide unit, and

Ulrike Braun; Bernhard Schartel; Mario A. Fichera; Christian Jäger

2007-01-01

310

Buildup of the acceptor emission as a result of energy transfer from Tb3+ to Sm3+ in barium borate glass  

Microsoft Academic Search

Intensity and lifetime data indicate that the self-quenching of Sm3+ fluorescence in barium borate glass matrix is by direct dipole-quadrupole interactions. The quenching of Tb3+ fluorescence by Sm3+ has been found due to direct dipole-dipole interactions. However, at relatively low Sm3+ concentrations, energy transfer through migration among Tb3+ ions also occurs. Further at low Sm3+ concentrations, there is an enhancement

A. K. Agarwal; N. C. Lohani; T. C. Pant; K. C. Pant

1984-01-01

311

Structural modifications and biological compatibility of doped bio-active glasses.  

PubMed

The Raman laser and infrared spectra of doped bio-active glasses of the 45S5 type are presented and discussed. The spectroscopic results show that the doping agents cause the destruction of the basic glass structure and the consequent formation of SiO4(4-) units in the glass network. When the doped glasses have been immersed in a physiological solution (199 medium), a film of calcite forms on the glass surface and this modification is related to the type of doping agent used, decisive for close linking between metal supports and the glass. The presence of doping agents does not prevent the normal growth of the bone onto the surface of doped bioactive glasses. Histological tests show that tissue response to very fine powders of doped glasses increases up to 15 days more or less according to the structural modifications revealed by spectroscopic measurements. PMID:3224140

Krajewski, A; Ravaglioli, A; Bertoluzza, A; Monti, P; Battaglia, M A; Pizzoferrato, A; Olmi, R; Moroni, A

1988-11-01

312

Crystallization behavior of rare-earth doped fluorochlorozirconate glasses.  

PubMed

A series of fluorochlorozirconate (FCZ) glasses, each doped with a different rare-earth, was prepared and examined to determine thermal stability and activation energy, Ea , of the dopant dependent BaCl2 crystallization. Non-isothermal differential scanning calorimetry (DSC) measurements were done to investigate the endothermic and exothermic reactions upon heat treatment of the glass samples. In comparison to the rare-earth free FCZ glass, significant changes in the Hruby constant, Hr , and Ea were found due to the addition of a rare-earth and also between the individual dopants. PMID:23493406

Paßlick, C; Ahrens, B; Henke, B; Johnson, J A; Schweizer, S

2011-06-01

313

Visible luminescence from Dy3+ doped tellurite glasses  

NASA Astrophysics Data System (ADS)

This paper reports on luminescence property of the Dy3+-doped tellurite glasses. The samples are studied by absorption and visible emission spectra. The measured emission spectrum of Dy3+ glass has revealed two main bands at 484 nm (4F9/2-->6H15/2) and 574 nm (4F9/2-->6H13/2) when pumping with the wavelength of 325 nm. The concentration quenching occurred as Dy3+ concentration increased beyond 2 mol%. The chromaticity coordinates of these samples are close to white light, which implies that the glasses might be a potential candidate for white lighting through an appropriate combination.

Zhang, Feng; Xiao, Zhisong; Yan, Lu; Zhu, Fang; Huang, Anping

2009-08-01

314

Photostimulated luminescence from BaCl2:Eu2+ nanocrystals in lithium borate glasses following neutron irradiation  

NASA Astrophysics Data System (ADS)

A glass-ceramic thermal neutron imaging plate material is reported. The material consists of a neutron sensitive 2B2O3-Li2O glass matrix containing nanocrystallites of the storage phosphor BaCl2:Eu2+. When doped with 0.5 mol % Eu2+, the neutron induced photostimulated luminescence (PSL) conversion efficiency of the 10B enriched glass-ceramic is around 60% of that a commercial neutron imaging plate, while the ? sensitivity is an order of magnitude lower than that of the commercial plate. A Eu2+-concentration series shows that the PSL efficiency for x rays is optimized at 0.01 mol % Eu2+. Thermoluminescence measurements indicate trap depths in BaCl2:Eu2+ ranging from 0.55 to 2.7 eV.

Appleby, G. A.; Edgar, A.; Williams, G. V. M.; Bos, A. J. J.

2006-09-01

315

Photostimulated luminescence from BaCl{sub 2}:Eu{sup 2+} nanocrystals in lithium borate glasses following neutron irradiation  

SciTech Connect

A glass-ceramic thermal neutron imaging plate material is reported. The material consists of a neutron sensitive 2B{sub 2}O{sub 3}-Li{sub 2}O glass matrix containing nanocrystallites of the storage phosphor BaCl{sub 2}:Eu{sup 2+}. When doped with 0.5 mol % Eu{sup 2+}, the neutron induced photostimulated luminescence (PSL) conversion efficiency of the {sup 10}B enriched glass-ceramic is around 60% of that a commercial neutron imaging plate, while the {gamma} sensitivity is an order of magnitude lower than that of the commercial plate. A Eu{sup 2+}-concentration series shows that the PSL efficiency for x rays is optimized at 0.01 mol % Eu{sup 2+}. Thermoluminescence measurements indicate trap depths in BaCl{sub 2}:Eu{sup 2+} ranging from 0.55 to 2.7 eV.

Appleby, G. A.; Edgar, A.; Williams, G. V. M.; Bos, A. J. J. [MacDiarmid Institute, Victoria University of Wellington, P.O. Box 600, Wellington (New Zealand); Industrial Research Limited, Wellington (New Zealand) and MacDiarmid Institute, Victoria University of Wellington, P.O. Box 600 Wellington (New Zealand); Faculty of Applied Sciences, Delft University of Technology, 2629 JB Delft (Netherlands)

2006-09-04

316

Novel fluorine-phosphate semiconductor doped glasses: Linear and nonlinear optical properties  

Microsoft Academic Search

We have synthesized a new type of high quality semiconductor doped glass (CdSSe embedded in a fluorine-phosphate matrix) using batch technology. The linear and nonlinear optical properties of this glass are investigated and compared with borosilicate glass doped with the same semiconductor. The optical susceptibility of glass is measured using degenerate four wave mixing technique.

B. Vaynberg; M. Matusovsky; M. Rosenbluh; V. Petrikov; A. Lipovskii

1997-01-01

317

Nonlinear optical properties of semiconductor-doped silica gel glass  

Microsoft Academic Search

Glass doped with semiconductor microcrystals in nanometer size has attracted much attention for its nonlinear optical properties. Compared with other semiconductor material preparation techniques, the sol-gel process is promising because it's a low temperature process and has many advantages such as high chemical purity, high microcrystal content, and narrow crystal size distribution. This paper describes the preparation, structure and optical

H. L. Liu; S. S. Wang; Y. Zhou; Q. C. Zhao; L. Y. Zhang; X. Yao

1996-01-01

318

Nonlinear optical properties of commercial semiconductor-doped glasses  

Microsoft Academic Search

We report new observations made on semiconductor-doped glasses commercially available. We have observed that the modulus of the Kerr susceptibility is proportional to the absorption coefficient below, across and above the gap. We have measured the phase of this susceptibility for various values of the excess energy. We have also observed a blue shift of the absorption edge following pulsed

P. Roussignol; D. Ricard; C. Flytzanis

1987-01-01

319

Compact, highly efficient ytterbium doped bismuthate glass waveguide laser.  

PubMed

Laser slope efficiencies close to the quantum defect limit and in excess of 78% have been obtained from an ultrafast laser inscribed buried channel waveguide fabricated in a ytterbium-doped bismuthate glass. The simultaneous achievement of low propagation losses and preservation of the fluorescence properties of ytterbium ions is the basis of the outstanding laser performance. PMID:22627539

Mary, R; Beecher, S J; Brown, G; Thomson, R R; Jaque, D; Ohara, S; Kar, A K

2012-05-15

320

Magnetic nanoparticles formed in glasses co-doped with iron and larger radius elements  

NASA Astrophysics Data System (ADS)

A new type of nanoparticle-containing glasses based on borate glasses co-doped with low contents of iron and larger radius elements, Dy, Tb, Gd, Ho, Er, Y, and Bi, is studied. Heat treatment of these glasses results in formation of magnetic nanoparticles, radically changing their physical properties. Transmission electron microscopy and synchrotron radiation-based techniques: x-ray diffraction, extended x-ray absorption fine structure, x-ray absorption near-edge structure, and small-angle x-ray scattering, show a broad distribution of nanoparticle sizes with characteristics depending on the treatment regime; a crystalline structure of these nanoparticles is detected in heat treated samples. Magnetic circular dichroism (MCD) studies of samples subjected to heat treatment as well as of maghemite, magnetite, and iron garnet allow to unambiguously assign the nanoparticle structure to maghemite, independently of co-dopant nature and of heat treatment regime used. Different features observed in the MCD spectra are related to different electron transitions in Fe3+ ions gathered in the nanoparticles. The static magnetization in heat treated samples has non-linear dependence on the magnetizing field with hysteresis. Zero-field cooled magnetization curves show that at higher temperatures the nanoparticles occur in superparamagnetic state with blocking temperatures above 100 K. Below ca. 20 K, a considerable contribution to both zero field-cooled and field-cooled magnetizations occurs from diluted paramagnetic ions. Variable-temperature electron magnetic resonance (EMR) studies unambiguously show that in as-prepared glasses paramagnetic ions are in diluted state and confirm the formation of magnetic nanoparticles already at earlier stages of heat treatment. Computer simulations of the EMR spectra corroborate the broad distribution of nanoparticle sizes found by ``direct'' techniques as well as superparamagnetic nanoparticle behaviour demonstrated in the magnetization studies.

Edelman, I.; Ivanova, O.; Ivantsov, R.; Velikanov, D.; Zabluda, V.; Zubavichus, Y.; Veligzhanin, A.; Zaikovskiy, V.; Stepanov, S.; Artemenko, A.; Curély, J.; Kliava, J.

2012-10-01

321

Impedance spectroscopic characterization of Sm2O3 containing lithium borate glasses.  

PubMed

27.5 Li2O-(72.5-X) B2O3-X Sm2O3 (X=0.5, 1, 1.5 and 2) were prepared by conventional melt quench technique. Impedance spectroscopy (IS) is used to study the electrical properties of these prepared glasses. Modulus formalism is introduced to study relaxation behaviour of these glasses. Scaling model shows the good overlap of data on single master curve which suggests that conduction mechanism in these glasses is compositional dependent. Variation of dielectric constant and dielectric loss with the addition of Sm2O3 and frequency are discussed here. PMID:24929310

Ramteke, D D; Gedam, R S

2014-12-10

322

Radiation-induced luminescence in terbium-doped silicate glasses  

NASA Astrophysics Data System (ADS)

The purpose of this study is to characterize radiation- induced luminescence of terbium-doped silicate glasses. Experiments performed investigated the optical properties, isothermal time-evolution, and temperature dependence of the radiation-induced luminescence of two commercially available terbium-doped glasses. A problem common to this type of glass is the persistent luminescence, or afterglow, that occurs following the end of excitation from an external source of radiation. While the processes that govern characteristic luminescence of rare earth ions, including terbium, are well understood, the processes that give rise to afterglow in doped glasses are not. Identifying the source of long-term luminescence is essential for controlling problems that may arise from practical applications of luminescent glasses. It was determined that the stimulation of terbium fluorescence is the result of direct excitation from the external radiation source, and indirect excitation from the delayed recombination of charge carriers releasing from traps in the host glass. The range of trap depths is found to be well represented by quasi-continuous distribution functions. The characteristic decay time during the initial response of both glasses studied is approximately 3.5 milliseconds. Decay of the afterglow was observed to persist for several hours, depending on the acquired dose of radiation. Comparison of the response to x-rays and ultraviolet radiation yielded the same results, indicating that the same processes are involved in producing afterglow for both cases. This result suggests a more efficient means of characterizing scintillating glasses by using ultraviolet lasers instead of x-rays.

West, Michael Stuart

1997-12-01

323

Effect of alkali addition on DC conductivity & thermal properties of vanadium-bismo-borate glasses  

NASA Astrophysics Data System (ADS)

The DC Conductivity and Differential Thermal Analysis of glasses with composition (30-x)Li2O?xV2O5?20Bi2O3?50B2O3(x=15, 10, 5) has been carried out in order to study the effect of replacing the Transition Metal Oxide (TMO) with alkali oxide. A significant increase in the DC conductivity has been observed with increase in alkali content. Again the thermal measurements have shown the decrease in both glass transition temperature (Tg) and crystallization temperature (Tx). The Glass Stability (GS) and Glass Forming Ability (GFA) have also been calculated and these also were found to decrease with increase in alkali oxide content at the cost of TMO.

Khasa, S.; Dahiya, M. S.; Agarwal, A.

2014-04-01

324

Laser-Induced Fluorescence Line Narrowing of Eu exp 3+ in Lithium Borate Glass.  

National Technical Information Service (NTIS)

Laser-induced fluorescence line narrowing has recently been used to investigate the local environment and interactions of paramagnetic ions in glass. Since the resulting spectra are sensitive to structural modifications, this technique was applied to stud...

M. J. Weber J. Hegarty D. H. Blackburn

1977-01-01

325

Effect of nucleating agents on the crystallisation behaviour of barium hexaferrite in a borate glass  

NASA Astrophysics Data System (ADS)

Glass-ceramics containing BaFe 12O 19 as the major crystalline phase have been prepared from glasses in the system BaO-Fe 2O 3-B 2O 3 by subjecting the latter to a suitable heat treatment schedule. Small concentrations (up to 1 mol%) of Ag 2O, Bi 2O 3, P 2O 5 and TiO 2, respectively, have been used to improve the crystallisation kinetics of the ferrite phase. Bi 2O 3 is found to be the most efficient nucleating agent in this process whereas TiO 2 inhibits the precipitation of any ferrite phase in the glass matrix. Detailed magnetic and EPR measurements have been carried out on all the glass ceramics prepared. The data are explained on the basis of microstructural characteristics as delineated by optical and transmission electron microscopy.

Ram, S.; Chakravorty, D.; Bahadur, D.

1986-12-01

326

Novel Tm 3+-doped fluorotellurite glasses with enhanced quantum efficiency  

NASA Astrophysics Data System (ADS)

In this paper, new highly Tm 3+-doped tellurite glasses with host composition 75TeO 2- xZnF 2- yGeO 2-12PbO-3Nb 2O 5 [ x(5-15), y(0-5) mol%] are presented and compared to the Tm-doped tellurite glasses based on the traditional host composition: 75TeO 2-20ZnO-5Na 2O mol%. Enhanced quantum efficiency from 3F 4 level was observed for the proposed glasses and thermal stability and viscosity values make them suitable for optical fiber drawing. Besides the host composition, substantial influence of Tm 3+ concentration on luminescence and lifetime of excited 3F 4 and 3H 4 states were discussed.

Gebavi, H.; Milanese, D.; Balda, R.; Ivanda, M.; Auzel, F.; Lousteau, J.; Fernandez, J.; Ferraris, M.

2011-01-01

327

Vibrational study of lithium sulfate based fast ionic conducting borate glasses  

Microsoft Academic Search

The influence of the sulfate anion on the structure of the xLiâO x yLiâSOâ x BâOâ fast ionic conducting glasses has been studied by Raman and Fourier-transform infrared spectroscopies, for compositions probing the whole glass-forming region (x = 0.20, 0.56; y = 0-0.50). Difference spectra are presented to elucidate the SOâ\\/sup 2 -\\/-induced structural changes. Thus, for the x =

E. I. Kamitsos; M. A. Karakassides; G. D. Chryssikos

1986-01-01

328

Structure-Property Relations in Barium Borate Glasses from Raman Scattering Data  

Microsoft Academic Search

Glasses in the xBaO-(100 ? x)B2O3 system (x = 16–50 mol %) are investigated by Raman spectroscopy. The spectral forms of stoichiometric groupings are separated from the experimental Raman spectra. The diagram of the content of these groupings in glasses is constructed. The diagram obtained makes it possible to calculate the densities, refractive indices, temperature coefficients of linear expansion, and

T. S. Markova; O. V. Yanush; I. G. Polyakova; B. Z. Pevzner; V. P. Klyuev

2005-01-01

329

Photosensitivity of Ge-doped phosphate glass to 244 nm irradiation  

SciTech Connect

UV photosensitivity of Ge-doped phosphate glasses is examined by writing photoinduced gratings in bulk glass samples. Radiation-induced index changes up to {approx}3.5x10{sup -5} were obtained by diffraction efficiency measurements of UV written gratings. In contrast to phosphate glasses without intentional doping, no significant photodarkening at visible wavelength was observed in Ge-doped phosphate glasses after UV exposure. The measured index changes demonstrate the potential of Ge-doped phosphate glasses for the fabrication of a fiber Bragg grating, a key component for phosphate-glass-based photonic devices.

Suzuki, S.; Schuelzgen, A.; Sabet, S.; Moloney, J. V.; Peyghambarian, N. [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States)

2006-10-23

330

Glass-crystal transition in silver-iodide-doped silver selenomolybdate glasses  

NASA Astrophysics Data System (ADS)

In this paper, we have studied the isothermal and non-isothermal glass-crystal transition in AgI-doped silver selenomolybdate glasses using differential scanning calorimetry. We have observed a strong dependence of AgI on the glass-crystal transition of these glasses. The activation energy for the crystallization and the dimensionality of the crystal growth for the isothermal and non-isothermal crystallization processes have been determined. The dimensionality of the crystal growth depends strongly on the AgI content and intriguingly shows different behavior when compared for isothermal and non-isothermal cases. For the present glass system the John-Mehl-Avrami model describes well the isothermal crystallization kinetics, while the Sestak-Berggren model is more suitable to describe the non-isothermal crystallization kinetics for glass-crystal transformation.

Deb, B.; Ghosh, A.

2013-12-01

331

XRD and FTIR structural investigation of gadolinium-zinc-borate glass ceramics  

NASA Astrophysics Data System (ADS)

X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy measurements have been employed to investigate the (GdO)?(BO)?(ZnO) glass ceramics system, with 0 ? x ? 15 mol%. After heat treatment applied at 860 °C for 2 h, some structural changes were observed and new crystalline phases appeared in the structure of the samples. In these glass ceramics four crystalline phases were identified using powder diffraction files (PDF 2), namely ZnBO, ZnO(BO), Zn(BO) and GdBO. From the XRD data, the average unit-cell parameter and the quantitative ratio of the crystallographic phases in the studied samples were evaluated. FTIR data revealed that the BO, BO and ZnO are the main structural units of these glass ceramics network. The compositional dependence of the different structural units which appear in the studied samples was followed.

Borodi, G.; Pascuta, P.; Stefan, R.; Dan, V.; Pop, V.; Radulescu, D.

2013-11-01

332

Helium diffusion in curium-doped borosilicate waste glass  

NASA Astrophysics Data System (ADS)

The isothermal release of helium from 244Cm-doped borosilicate glass has been studied as a function of time at different annealing temperatures. Helium measurements were performed using a micro gas chromatograph coupled to a furnace installed in a hot cell at ATALANTE nuclear research facility. Plane-parallel glass samples were prepared from glass discs that had been stored for 5.1 years at room temperature, accumulating around 10 19 alpha decays per gram of glass, a level that will be reached in current nuclear glass packages several thousand years after disposal. The experimental helium release data were simulated using a 3D numerical model to determine the helium diffusion coefficients. The extracted diffusion coefficients follow the Arrhenius law with an activation energy of 0.61 ± 0.03 eV and a pre-exponential factor of (5.7 ± 1.6) × 10 -3 cm 2 s -1. The results were compared with literature data on damaged and undamaged glasses to assess the effect of glass damage on helium release. The helium release results are consistent with a thermal diffusion mechanism involving only one population of helium atoms. The helium diffusion coefficients were unaffected by the glass alpha damage.

Fares, T.; Peuget, S.; Bouty, O.; Deschanels, X.; Magnin, M.; Jégou, C.

2011-09-01

333

Effect of nucleating agents on the crystallisation behaviour of barium hexaferrite in a borate glass  

Microsoft Academic Search

Glass-ceramics containing BaFe12O19 as the major crystalline phase have been prepared from glasses in the system BaO-Fe2O3-B2O3 by subjecting the latter to a suitable heat treatment schedule. Small concentrations (up to 1 mol%) of Ag2O, Bi2O3, P2O5 and TiO2, respectively, have been used to improve the crystallisation kinetics of the ferrite phase. Bi2O3 is found to be the most efficient

S. Ram; D. Chakravorty; D. Bahadur

1986-01-01

334

Photostimulated luminescence in Eu-doped fluorochlorozirconate glass ceramics  

NASA Astrophysics Data System (ADS)

We report the synthesis of Eu2+- and chlorine-doped fluorozirconate glass-ceramics that show an intense photostimulated luminescence (PSL) after x-ray irradiation at room temperature. The PSL efficiency is up to 80% of that found in the well-known crystalline x-ray storage phosphor BaFBr:Eu2+, and it is the largest thus far reported for a glass-ceramic. We attribute the PSL to crystallites of orthorhombic BaCl2 that are formed after annealing above the glass temperature. Hexagonal BaCl2 crystallites are also observed after short annealing times, but they do not provide a measurable PSL signal. The photoluminescence peak from glass-ceramics containing orthorhombic BaCl2 crystallites occurs at 402 nm, and the stimulation band is centered at about 560 nm.

Schweizer, Stefan; Hobbs, Linn W.; Secu, Mihail; Spaeth, Johann-Martin; Edgar, Andrew; Williams, Grant V. M.

2003-07-01

335

Emission characteristics of Dy3+ ions in lead antimony borate glasses  

NASA Astrophysics Data System (ADS)

Glasses with the composition 30PbO-25Sb2O3-(45- x)B2O3- xDy2O3 for x=0 to 1 were prepared in steps of 0.2 by the melt-quenching method. Various physical parameters, viz., density, molar volume, and oxygen packing density, were evaluated. Optical absorption and luminescence spectra of all the glasses were recorded at room temperature. From the observed absorption edges optical band gap, the Urbach energies are calculated; the optical band gap is found to decrease with the concentration of Dy2O3. The Judd-Ofelt theory was applied to characterize the absorption and luminescence spectra of Dy3+ ions in these glasses. Following the luminescence spectra, various radiative properties, like transition probability A, branching ratio ? and the radiative life time ? for different emission levels of Dy3+ ions, have been evaluated. The radiative lifetime for the 4F9/2 multiplet has also been evaluated from the recorded life time decay curves, and the quantum efficiencies were estimated for all the glasses. The quantum efficiency is found to increase with the concentration of Dy2O3.

Chandra Shekhar Reddy, M.; Appa Rao, B.; Brik, M. G.; Prabhakar Reddy, A.; Raghava Rao, P.; Jayasankar, C. K.; Veeraiah, N.

2012-08-01

336

Pr3+-doped phosphate glasses for fiber amplifiers operating at 1.38–1.53 ?m of the fifth optical telecommunication window  

NASA Astrophysics Data System (ADS)

Effective near-infrared emission covering the fifth optical telecommunication window (1380–1525 nm) has been observed in Pr3+-doped phosphate (LCBALP) glasses. Judd–Ofelt parameters ?2 (9.17 × 10–20 cm2), ?4 (16.50 × 10–20 cm2) and ?6 (2.41 × 10–20 cm2) indicate a high inversion asymmetrical and strong covalent environment in the optical glasses. The effective bandwidth (??eff) of the corresponding 1D2 ? 1G4 transition emission is obtained to be 148 nm, and the maximum stimulated emission cross-section (?em) at 1467.5 nm is derived to be 1.29 × 10–20 cm2. The quantum efficiency of Pr3+:1D2 level is identified to be 85.36%. The broad effective bandwidth and the large emission cross-section profile indicate that Pr3+-doped LCBALP glass fiber is promising in the realization of effective broadband amplification, especially at E- and S-band. As an expectation, the mature oxide glasses with Pr3+-doping, such as borate, phosphate and silicate glasses, are expected to be attractive candidates for broadband signal amplifiers operating at the fifth optical telecommunication window.

Han, Xiaozhe; Shen, Lifan; Pun, Edwin Yue Bun; Ma, Tiecheng; Lin, Hai

2014-05-01

337

Gadolinium doping of vanadate-tellurate glasses and glass ceramics  

Microsoft Academic Search

In order to further elucidate the local structure of ternary xGd2O3(100 ? x)[0.7TeO2 · 0.3V2O5] glasses with x = 0, 5, 10, 15, 20 mol%, FTIR spectroscopy, XRD diffraction and density measurement were performed. FTIR and density data\\u000a show that by increasing the gadolinium ions content of the samples the excess of oxygen may be accommodated by the inter-conversion\\u000a of some [VO4] into [VO5] structural units

Simona Rada; Eugen Culea; Monica Culea

2008-01-01

338

Silver doped nanobioactive glass particles for bone implant applications  

SciTech Connect

Silica based silver doped nanobioactive glass compositions (58SiO{sub 2}-33CaO-9P{sub 2}O{sub 5} and 58SiO{sub 2}-23CaO-9P{sub 2}O{sub 5}-10Ag{sub 2}O(mol%)) were synthesized by a simple sol-gel route. The prepared samples were comprehensively characterised by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and scanning electron microscopic studies. The results reveal that the prepared samples have amorphous phase with spherical morphology and having a particle size less than 100 nm. The specific surface areas were 90 and 61 m{sup 2}g{sup -1} respectively. The in vitro bioactivity of glass samples were confirmed by the formation of hydroxyapatite layer on glass surfaces. The Ag{sub 2}O-doped nanobioactive glasse samples shows reveal significant antibacterial activity compare with base glasses.

Prabhu, M.; Kavitha, K.; Karunakaran, G.; Manivasakan, P.; Rajendran, V. [Centre for Nanoscience and Technology, K. S. Rangasamy College of Technology, Tiruchengode - 637215, Namakkal (DT), Tamil Nadu (India)

2013-02-05

339

Optical absorption spectrum of dysprosium doped zinc phosphate glass  

NASA Astrophysics Data System (ADS)

Optical properties of Dy 3+ doped zinc phosphate glasses have been investigated. In the present study glasses with the composition xZnO · (1- x)P 2O 5 (0.5? x?0.7) (typical value of x=0.667) containing 0.5 mol weight of Dy 2O 3 are prepared. The density of the glass is determined by Archimedes's principle and the refractive index is measured on Abbe refractometer using sodium lamp as light source. The optical absorption spectra are recorded on a Hitachi U-3400 spectrophotometer in the wavelength range 200-2500 nm. Using the Judd-Ofelt (JO) theory, the intensity parameters ( ? ?, ?=2, 4,6) have been evaluated for the glass. These intensity parameters are used to predict radiative properties that include electric ( Sed) and magnetic ( Smd) dipole line strengths, radiative ( A) and total radiative ( AT) transition probabilities, lifetimes ( ?R), branching ratios ( ?R) for the excited ( 6H 11/2, 6F 11/2, 6F 9/2, 6F 7/2, 6F 5/2, 6F 3/2) levels of these Dy 3+ doped phosphate glass.

Chandrasekhar, A. V.; Radhapathy, A.; Reddy, B. J.; Reddy, Y. P.; Ramamoorthy, L.; Ravikumar, R. V. S. S. N.

2003-05-01

340

Mechanism for doping in Bi chalcogenide glasses  

Microsoft Academic Search

The structural environment of Bi incorporated in Ge chalcogenide glasses has been found from extended x-ray absorption fine-structure data to consist of threefold coordination. An increase by a factor of 2 in the Debye-Waller factor occurs as the carrier type changes from p to n. A mechanism involving the suppression of positively charged structural defects, and the consequent unpinning of

S. R. Elliott; A. T. Steel

1986-01-01

341

Luminescence and scintillation of Ce3+-doped high silica glass  

NASA Astrophysics Data System (ADS)

Ce3+-doped high silica glass was prepared by impregnation of Ce ions into a porous silica glass followed by high temperature sintering in a CO reducing atmosphere. The characteristic emission of Ce3+ 5d ? 4f transition peaking around 375 nm is observed in its luminescence spectra under UV and X-ray excitation. Its photoluminescence decay is governed by several tens of nanoseconds decay time. Its integral scintillation efficiency is comparable to that of a Bi4Ge3O12 (BGO) crystal under X-ray excitation. Scintillation light yield under gamma and alpha excitation was measured and compared with that of BGO.

Chewpraditkul, Weerapong; Shen, Yinglong; Chen, Danping; Yu, Bingkun; Prusa, Petr; Nikl, Martin; Beitlerova, Alena; Wanarak, Chalerm

2012-09-01

342

Spectral hole burning in thulium-doped glass ceramics.  

PubMed

We have used spectral hole burning to measure the homogeneous linewidth of the (3)H(6)(1)- (3)F(3)(1) transition of Tm(3+) ions doped into oxyfluoride glass ceramics consisting of nanocrystals of LaF(3) in an aluminosilicate glass matrix. From the magnitude of the hole width in the nanocrystals and its dependence on temperature, we propose that excitation of tunneling modes in the adjacent glassy phase as well as of confined mechanical modes in the nanocrystals is responsible for the broadening. PMID:18040343

Macfarlane, R M; Dejneka, M J

2001-04-01

343

Diode pumped white light emission from dysprosium and samarium doped glasses  

NASA Astrophysics Data System (ADS)

Glasses embedded with Dysprosium and Samarium were made by the melt quenching technique. Dy3+ -doped glasses exhibited bright white luminescence under 10 mW of 405 nm diode laser excitation. Color rending index of the glass was improved by adding Sm3+ as a co-dopant to the glass. Spectroscopic results of the glasses are discussed.

Reddy, B. Rami; Edwards, Vernessa M.; Surabhi, Raja

2014-03-01

344

Spectroscopic and lasing properties of highly-doped Ytterbium-glasses  

Microsoft Academic Search

Ytterbium (Yb) doped glass is expected as next generation high-performance solid laser material. However, the laser glasses have a problem that the ions-doping-concentration is much lower than crystals. In this study, we make highly-doped Ytterbium-ions glasses (YbF3-BaF2-AlF3-GeO2, YbBAG), and succeeded laser oscillations of 20 mol.% Ytterbium-ions glass. The highly-doped Ytterbium-ions glasses are much suitable for short-fiber or waveguide lasers.

Kenta Sasaki; Hiroshi Furuta; Susumu Yonezawa; Shinichi Matsubara; Seiji Watanabe; Tatsuya Igarashi; Yutaka Kondo; Yoshinobu Sasatani; Hiroyuki Hitotsuya; Sakae Kawato

2011-01-01

345

IR and EPR studies on some lithium-borate glasses with vanadium ions  

Microsoft Academic Search

The IR spectra of the xV2O5(100?x)[2B2O3·Li2O] glasses contain the bands characteristic for B2O3(?(B–O–B)=700cm?1, ??(B–O)=1250cm?1), Li2O (??(Li–O)=415cm?1) and V2O5(??(V–O)=950cm?1) groups. EPR spectra for the glasses with small contents of V2O5(x?5mol%) show a well-resolved hyperfine structure typical for isolated vanadyl ions in a ligand field of near octahedral (Oh) symmetry. For x>20mol% the EPR spectra may be considered as a superposition of

O. Cozar; I Ardelean; I Bratu; S Simon; C Craciun; L David; C Cefan

2001-01-01

346

[Study on rare earth doped long luminescence glass].  

PubMed

A luminosilicate glass samples doped with Eu203 and Dy2O3 were prepared under the air and reducing atmosphere respectively. The excitation spectra, emission spectra and thermal luminescence spectra of the samples prepared under different atmosphere were measured. Luminescence mechanism of the afterglow glasses wa s analyzed. The results showed that the sample prepared under an ambient atmosphere has no afterglow. Its excitation and emission spectra showed the typical transitions of (5)Di( i = 0, 1) --> (7)Fj (j = 0-4) from Eu3+ but the sample reheated at a reducing atmosphere has afterglow. The sample doped with Eu2+ shows luminescence peaking at 462 nm. And the sample codoped with Eu2+ and Dy3+ shows luminescence peaking at 457 nm. The afterglowluminescence can last more than 12 h. PMID:16499036

Zhang, Xi-yan; Mi, Xiao-yun; Xiao, Zhi-yi; Liu, Quan-sheng

2005-11-01

347

Spectroscopic ellipsometry investigations of Eu-doped oxy-fluoride glass and glass-ceramics  

NASA Astrophysics Data System (ADS)

Oxyfluoride glass-ceramics in the system SiO2-Al2O3-CaF2-EuF3 containing Eu3+-doped CaF2 nanocrystals were produced by using controlled crystallization of melt-quenched glass. X-ray diffraction and scanning electron microscopy data have revealed the formation of CaF2 nanocrystals of about 50 nm size. The Eu3+-dopant ions act as the nucleating agent necessary to initiate the crystallization process. The refractive index is higher in the glass ceramics than in the initial glass and varies as the annealing time increases. Two competitive processes are responsible for this behavior, the crystallization of the CaF2 phase and the decrease of the glass ceramic mass density.

Galca, A. C.; Preda, N.; Secu, C. E.; Luculescu, C. R.; Secu, M.

2012-06-01

348

Visible and near infrared luminescence properties of Er3+-doped LBTAF glasses for optical amplifiers  

NASA Astrophysics Data System (ADS)

Trivalent erbium doped lead borate titanate aluminum fluoride (LBTAFEr) glasses of molar composition (50-x)PbO·30H3BO3·10TiO2·10AlF3·xEr2O3 were prepared and characterized applying the Judd-Ofelt theory. The visible and near infrared luminescence spectra obtained by exciting the samples at 486 nm (xenon source) and 514.5 nm (Ar+ laser) radiations exhibit (2H11/2, 4S3/2) ? 4I15/2 (547 nm) and 4I13/2 ? 4I15/2 (1.53 ?m) transitions, respectively. Thermalization of the two emitting 2H11/2 and 4S3/2 states is taken into account in calculating the significant radiative properties. The intensity parameters are used to calculate the transition probabilities, luminescence branching ratios, radiative decay times and emission cross-sections for the observed emission bands. The McCumber theory has been applied to evaluate the emission cross-section using the absorption cross-section of the 4I13/2 ? 4I15/2 transition of Er3+ ion. The decay profiles of the (2H11/2, 4S3/2) emission state were recorded and analyzed.

Jamalaiah, B. C.; Suhasini, T.; Rama Moorthy, L.; Janardhan Reddy, K.; Kim, Il-Gon; Yoo, Dong-Sun; Jang, Kiwan

2012-03-01

349

Bose glass and Mott glass of quasiparticles in a doped quantum magnet.  

PubMed

The low-temperature states of bosonic fluids exhibit fundamental quantum effects at the macroscopic scale: the best-known examples are Bose-Einstein condensation and superfluidity, which have been tested experimentally in a variety of different systems. When bosons interact, disorder can destroy condensation, leading to a 'Bose glass'. This phase has been very elusive in experiments owing to the absence of any broken symmetry and to the simultaneous absence of a finite energy gap in the spectrum. Here we report the observation of a Bose glass of field-induced magnetic quasiparticles in a doped quantum magnet (bromine-doped dichloro-tetrakis-thiourea-nickel, DTN). The physics of DTN in a magnetic field is equivalent to that of a lattice gas of bosons in the grand canonical ensemble; bromine doping introduces disorder into the hopping and interaction strength of the bosons, leading to their localization into a Bose glass down to zero field, where it becomes an incompressible Mott glass. The transition from the Bose glass (corresponding to a gapless spin liquid) to the Bose-Einstein condensate (corresponding to a magnetically ordered phase) is marked by a universal exponent that governs the scaling of the critical temperature with the applied field, in excellent agreement with theoretical predictions. Our study represents a quantitative experimental account of the universal features of disordered bosons in the grand canonical ensemble. PMID:22996552

Yu, Rong; Yin, Liang; Sullivan, Neil S; Xia, J S; Huan, Chao; Paduan-Filho, Armando; Oliveira, Nei F; Haas, Stephan; Steppke, Alexander; Miclea, Corneliu F; Weickert, Franziska; Movshovich, Roman; Mun, Eun-Deok; Scott, Brian L; Zapf, Vivien S; Roscilde, Tommaso

2012-09-20

350

Er 3+-doped tellurite glass waveguides produced by fiber on glass (FOG) method  

NASA Astrophysics Data System (ADS)

In this work we used a Thermal Mechanic Analysis equipment to produce the channel FOG waveguides by pressing an Er 3+ doped tellurite glass optical fiber against one Er 3+ ion doped tellurite glass substrate kept under T c +/- 30 °C (T c = soft point). The luminescence and waveguide refractive index were measured. Scanning electron microscopy was used to observe the obtained structure. The objective is to produce a new concept in components of integrated optical circuits. Then this work report the production of Er 3+-doped tellurite glass channel waveguides using the novel concept of Benson et al [1] of fiber on glass (FOG). To succeed with this technique it is important to correlate the main thermo-physical characteristics of the substrate and the fiber, which are the transition temperature T g, the temperature of the onset of crystallization T x, the maximum crystallization temperature T c and the thermal expansion coefficient. The T g, T x and T c values were determined by Differential Thermal Analysis (DTA), while the thermal expansion coefficient was determined by Thermal Mechanical Analysis (TMA). For the FOG purpose the thermal stability range, T x - T g, is an important temperature region which defines if the glass will have enough viscosity to shape in the FOG concept.

Rivera, V. A. G.; Rodriguez, E.; Chillcce, E. F.; Mazali, I. O.; Cesar, C. L.; Barbosa, L. C.

2006-03-01

351

Optical waveguide amplifiers based on Er-doped phosphate glasses  

NASA Astrophysics Data System (ADS)

Currently, there is a strong interest in developing planar waveguide amplifiers at 1.53 ?m with small dimensions of only a few centimeters. Trivalent Er shows a light emission around 1.53 ?m because of its intra- 4f transition. Er-doped planar waveguide amplifiers have potential applications in optical telecommunication and signal processing systems as integrated devices. Several multicomponent phosphate glasses, highly doped with Er ions, are prepared by common glass melting techniques. By applying a special heat-treatment on the as-melted glasses, the photoluminescence lifetime of Er ions for the 4I13/2-[4I]15/2 transition increases substantially, typically from 1-2 ms up to 7 ms for a sample doped with 2 mole % Er2O3. The increase of the photoluminescence lifetime is ascribed to a decrease in concentration of hydroxyl groups incorporated in the glass, which is confirmed by IR absorption spectroscopic measurements. The luminescence concentration quenching mechanism by hydroxyl groups is modelled. RF-sputtering techniques are applied to produce Er-doped phosphate glass waveguides on silicon substrates. The optimized Er-doped phosphate glass disks are used as the sputtering targets. The films are deposited in an O2/Ar atmosphere at a low pressure. A waveguide background loss as low as 0.9 dB/cm has been achieved at 1.3 ?m. A strip-loaded waveguide structure is applied to fabricate the channel waveguides, with a minimized influence on Er luminescence properties. Finally, net gain of 4.1 dB at 1.535 ?m is measured for a 10 mm long waveguide with a launched pump power of 21 mW at 980 nm. The amplifying properties of the waveguide are modelled and the upconversion coefficient is determined to be 2.6×10-18 cm- 3/s, one of the lowest among the known Er host materials. Furthermore, the model shows that it is feasible to achieve an optical gain of more than 20 dB by increasing the waveguide length to 4.9 cm. In conclusion, a comprehensive study has been conducted on the development of an optical waveguide amplifier at 1.53 ?m, including material host optimization, device fabrication and optical characterization. The study is of great significance for optical telecommunication and other related areas.

Yan, Yingchao

1997-07-01

352

Ce doped hafniate scintillating glasses: thermally stimulated luminescence and photoluminescence  

Microsoft Academic Search

Thermally stimulated luminescence (TSL) and time resolved luminescence studies have been performed on undoped, and Ce3+ and Mn2+ doped fluoro-hafniate glasses (HFG). The X-ray induced TSL glow curve above room temperature features different broad structures extending up to 350°C; wavelength resolved measurements put in evidence the existence of two distinct emission peaks around 300 and 550 nm, attributed to Ce3+

M. Martini; F. Meinardi; A. Vedda; I. Dafinei; P. Lecoq; M. Nikl

1996-01-01

353

Preparation of antibacterial silver-doped silica glass microspheres.  

PubMed

Various types of inorganic substances doped with silver ions have been developed as antibacterial materials, and some have already been commercialized. Colorless and chemically durable materials that slowly release silver ions are, however, still need to be developed. The present authors have previously shown that when a silica glass doped with silver and aluminium ions is prepared using the sol-gel method, the resultant product is colorless, chemically durable, and slowly releases silver ions into water over a long period. The doped silica glass takes a form of microspheres <1 microm in diameter, it is easily mixed with organic polymers, and the mixture can be formed into a thin film or fine fibers, etc. We report on the preparation of silver doped silica glass microspheres having a diameter =1 microm, using the sol-gel method. Initially, tetraethoxysilane was partially prehydrolyzed by water in ethanol, and then aluminium triisopropoxide was added to the solution to form Si-O-Al bonds. Finally, an ammonia solution containing silver nitrate was added to form silica microspheres doped with silver ion together with aluminium ions. The results show monodispersed microspheres 0.4-0.6 microm in diameter were obtained with nominal compositions of Si/Al/Ag = 1/0.01-0.03/0.003-0.03, with a molar ratio of Al/Ag = 1-3.3. The microspheres were colorless, showed a high chemical durability, and slowly released silver ions into water at 37 degrees C. Microspheres with the composition Si/Al/Ag = 1/0.01/0.01 showed excellent antibacterial activity against Escherichia coli. The minimum inhibitory concentration (MIC) of the microspheres was 400, which is less than the MIC value (800) of commercial antibacterial materials. PMID:12888996

Kawashita, Masakazu; Toda, Shogo; Kim, Hyun-Min; Kokubo, Tadashi; Masuda, Noriaki

2003-08-01

354

Spectroscopic properties of -doped K-Sr-Al phosphate glasses  

NASA Astrophysics Data System (ADS)

Trivalent holmium-doped K-Sr-Al phosphate glasses (--SrO--) were prepared, and their spectroscopic properties have been evaluated using absorption, emission, and excitation measurements. The Judd-Ofelt theory has been used to derive spectral intensities of various absorption bands from measured absorption spectrum of 1.0 mol% -doped K-Sr-Al phosphate glass. The Judd-Ofelt intensity parameters (, ) have been determined of the order of , , and , which in turn used to derive radiative properties such as radiative transition probability, radiative lifetime, branching ratios, etc. for excited states of ions. The radiative lifetimes for the , , and levels of ions are found to be 169, 296, and 317 ?s, respectively. The stimulated emission cross-section for 2.05-?m emission was calculated by the McCumber theory and found to be . The wavelength-dependent gain coefficient with population inversion rate has been evaluated. The results obtained in the titled glasses are discussed systematically and compared with other -doped systems to assess the possibility for visible and infrared device applications.

Linganna, K.; Rathaiah, M.; Venkatramu, V.; Jayasankar, C. K.

2014-05-01

355

Luminescence characteristics of Li?CO?-K?CO?-H?BO? glasses co-doped with TiO?/MgO.  

PubMed

Understanding the influence of co-dopants in the luminescence enhancement of carbonate glasses is the key issue in dosimetry. A series of borate glasses modified by lithium and potassium carbonate were synthesized by the melt-quenching method. The glass mixture activated with various concentrations of TiO2 and MgO was subjected to various doses of gamma-rays ((60)Co). The amorphous nature of the samples was confirmed by x-ray diffraction (XRD) spectra. The simple glowing curve of the glass doped with TiO2 features a peak at 230°C, whose intensity is maximal at 0.5 mol% of the dopant. The intensity of the glowing curve increases with the concentration of MgO added as a co-dopant up to 0.25 mol%, where it is two times higher than for the material without MgO thermoluminescence properties, including dose response, reproducibility, and fading were studied. The effective atomic number of the material was also determined. Kinetic parameters, such as kinetics order, activation energy, and frequency factor are estimated. The photoluminescence spectra of the titanium-doped glass consist of a prominent peaks at 480 nm when laser excitation at 650 nm is used. A three-fold photoluminescence enhancement and a blue shift of the peak were observed when 0.1% MgO was introduced. In addition, various physical parameters, such as ion concentration, polaron radius and internuclear distances were calculated. The mechanism for the thermoluminescence and photoluminescence enhancements are discussed. PMID:23948307

Alajerami, Yasser Saleh Mustafa; Hashim, Suhairul; Ghoshal, Sib Krishna; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Ibrahim, Zuhairi; Kadni, Taiman; Bradley, David Andrew

2013-12-01

356

Infrared spectroscopy of network and cation dynamics in binary and mixed alkali borate glasses  

Microsoft Academic Search

Infrared reflectance spectra of twenty different glasses of the type (B2O3)1-x-y(Li2O)x(Cs2O)y have been measured in the frequency range of 10–5000 cm?1. From these spectra, infrared absorbance and dielectric spectra have been calculated using the Kramers-Krönig inversion technique. The mid-infrared parts of the spectra are discussed in connection with B?O network vibrational modes. The far-infrared parts of the spectra yield cation

A. H. Verhoef; H. W. den Hartog

1995-01-01

357

Scintillating glass doped with organic activator p-TP and/or POPOP  

NASA Astrophysics Data System (ADS)

Two organic activators, p-TP(p-terphenyl) and POPOP (1,4-bis(5-phenyloxazol-2-yl) benzene), which are normally used to prepare the scintillating plastic, were doped in tin fluorephosphate glasses to develop a serial of scintillating glasses with different concentrations. The fluorescence spectra and the transmission spectra of some scintillating glass were explored and the actual concentration organic in scintillating glass was estimated by comparing the extracted solution from glass with standard solution. Results show that the organic materials can be doped into inorganic glass, however, the actual concentration of organics doped in the glass is very low. Compared with scintillating plastic, the emission peak of scintillating glasses move towards the longer wavelength and POPOP is not wavelength shift any more. Keywords: Scintillating glass, doping, organic activator, concentration

Zhu, Dogmei; Luo, Fa; Zhao, Hongsheng; Zhou, Wancheng

2006-01-01

358

Influence of Ce 3+ doping on the structure and luminescence of Er 3+-doped transparent glass-ceramics  

Microsoft Academic Search

Transparent glass-ceramics possess high thermal and mechanical properties, easy shaping allowing fibers elaboration and easy synthesis. However, previously studied Yb:Er-doped glass-ceramics do not appear efficient enough for optical amplification at 1.5?m in the telecommunication window. So, the addition of Ce3+ doping ions was performed.Oxyfluoride glasses (GeO2–PbO–PbF2) doped with ErF3, YbF3 and CeF3 were prepared and heated above glass transition temperature

G. Dantelle; M. Mortier; D. Vivien; G. Patriarche

2006-01-01

359

Electron Spin Resonance and optical absorption spectroscopic studies of manganese centers in aluminium lead borate glasses  

NASA Astrophysics Data System (ADS)

Electron Spin Resonance (ESR) and optical absorption studies of 5Al2O3 + 75H3BO3 + (20-x)PbO + xMnSO4 (where x = 0.5, 1,1.5 and 2 mol% of MnSO4) glasses at room temperature have been studied. The ESR spectrum of all the glasses exhibits resonance signals with effective isotropic g values at ?2.0, 3.3 and 4.3. The ESR resonance signal at isotropic g ? 2.0 has been attributed to Mn2+ centers in an octahedral symmetry. The ESR resonance signals at isotropic g ? 3.3 and 4.3 have been attributed to the rhombic symmetry of the Mn2+ ions. The zero-field splitting parameter (zfs) has been calculated from the intensities of the allowed hyperfine lines. The optical absorption spectrum exhibits an intense band in the visible region and it has been attributed to 5Eg ? 5T2g transition of Mn3+centers in an octahedral environment. The optical band gap and the Urbach energies have been calculated from the ultraviolet absorption edges.

SivaRamaiah, G.; LakshmanaRao, J.

2012-12-01

360

Electron Spin Resonance and optical absorption spectroscopic studies of manganese centers in aluminium lead borate glasses.  

PubMed

Electron Spin Resonance (ESR) and optical absorption studies of 5Al(2)O(3)+75H(3)BO(3)+(20-x)PbO+xMnSO(4) (where x=0.5, 1,1.5 and 2 mol% of MnSO(4)) glasses at room temperature have been studied. The ESR spectrum of all the glasses exhibits resonance signals with effective isotropic g values at ?2.0, 3.3 and 4.3. The ESR resonance signal at isotropic g?2.0 has been attributed to Mn(2+) centers in an octahedral symmetry. The ESR resonance signals at isotropic g?3.3 and 4.3 have been attributed to the rhombic symmetry of the Mn(2+) ions. The zero-field splitting parameter (zfs) has been calculated from the intensities of the allowed hyperfine lines. The optical absorption spectrum exhibits an intense band in the visible region and it has been attributed to (5)E(g)?(5)T(2g) transition of Mn(3+)centers in an octahedral environment. The optical band gap and the Urbach energies have been calculated from the ultraviolet absorption edges. PMID:23000927

SivaRamaiah, G; LakshmanaRao, J

2012-12-01

361

IR and EPR studies on some lithium-borate glasses with vanadium ions  

NASA Astrophysics Data System (ADS)

The IR spectra of the xV 2O 5(100- x)[2B 2O 3·Li 2O] glasses contain the bands characteristic for B 2O 3( ?(B-O-B)=700 cm -1, ?¯(B-O)=1250 cm -1), Li 2O ( ?¯(Li-O)=415 cm -1) and V 2O 5( ?¯(V-O)=950 cm -1) groups. EPR spectra for the glasses with small contents of V 2O 5(x?5 mol%) show a well-resolved hyperfine structure typical for isolated vanadyl ions in a ligand field of near octahedral ( Oh) symmetry. For x>20 mol% the EPR spectra may be considered as a superposition of two signals: one with the resolved hyperfine structure for isolated VO 2+ ions in a C4 v symmetry and another broad line without structure at g?1.96 for associated vanadium ions. The clustered ions are due to the dipole-dipole interactions between V 4+ ions and their number increases with the V 2O 5 content. The spectroscopic studies indicate that the V 2O 5 oxide becomes a former of the network at high concentration (x>20 mol%) together with B 2O 3.

Cozar, O.; Ardelean, I.; Bratu, I.; Simon, S.; Craciun, C.; David, L.; Cefan, C.

2001-05-01

362

Characterization of borate glasses by W-band pulse electron-nuclear double resonance spectroscopy  

SciTech Connect

(100-x) mol % B{sub 2}O{sub 3} x mol %Me{sub 2}O (Me=Li,Na,K) glasses, exposed to {gamma}-{sup 60}Co irradiation to produce paramagnetic states, were characterized by W-band (95 GHz) pulse electron-nuclear double resonance (ENDOR) spectroscopy in order to characterize local structures occurring in the range of compositions between x=16 and x=25 at which the 'boron oxide' anomaly occurs. The high resolution of nuclear frequencies allowed resolving the {sup 7}Li and {sup 11}B ENDOR lines. In the samples with x=16 and x=20 glasses, {sup 11}B hyperfine couplings of 16, 24, and 36 MHz were observed and attributed to the tetraborate, triborate, and boron oxygen hole center (BOHC) structures, respectively. The x=25 samples showed hyperfine couplings of 15 MHz for the tetraborate and 36 MHz for BOHC. Density functional theory (DFT) calculations predicted for these structures negative hyperfine couplings, which were confirmed by W-band ENDOR. This suggests that a spin polarization mechanism accounts for the negative hyperfine structure splitting.

Kordas, George [Sol Gel Laboratory for Glass and Ceramics, Institute of Materials Science, NCSR 'Demokritos', 15310 Aghia Paraskevi Attikis (Greece); Goldfarb, Daniella [Department of Chemical Engineering, Weizmann Institute of Science, 76100 Rehovot (Israel)

2008-10-21

363

Dy(3+)-doped zinc fluorophosphate glasses for white luminescence applications.  

PubMed

Dysprosium (Dy(3+)) ions doped zinc fluorophosphate (PKAZLFDy: P2O5-K2O-Al2O3-ZnF2-LiF-Dy2O3) glasses have been prepared and investigated their spectroscopic properties using absorption, emission and decay measurements. Judd-Ofelt analysis has been carried out to obtain the intensity parameters and in turn predicted radiative properties for the (4)F9/2 level of 1.0 mol% of Dy2O3 doped glass. Visible luminescence spectra have been obtained due to (4)F9/2?(6)HJ (J=11/2, 13/2, 15/2) transitions of Dy(3+) ions under 385 nm excitation. The yellow-to-blue luminescence intensity ratios and chromaticity coordinates of Dy(3+) ions in these glasses have been analyzed as a function of Dy(3+) ion concentration. The decay profiles for the (4)F9/2 level exhibit perfectly single exponential at lower concentrations (up to 1.0 mol%) and turn into non-exponential for higher concentrations (>1.0 mol%) due to energy transfer between donor (excited state Dy(3+) ion) and acceptor (ground state Dy(3+) ion). The results reveal that these glasses emit bright white light which is suitable for the development of W-LEDs. PMID:23719414

Vijaya, N; Upendra Kumar, K; Jayasankar, C K

2013-09-01

364

Optical properties of samarium doped zinc phosphate glasses  

NASA Astrophysics Data System (ADS)

Samarium doped zinc phosphate glasses having composition Sm2O3 (x)ZnO(60-x) P2O5 (40) (where x=0.1 0.5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been calculated. The values of density range from 3.34 to 3.87 gm/cm3 and those of molar volume range from 27.62 to 31.80 cm-3. The optical absorbance studies were carried out on these glasses to measure their energy band gaps. The absorption spectra of these glasses were recorded in UV-visible region. No sharp edges were found in the optical spectra, which verifies the amorphous nature of these glasses. The optical band gap energies for these glasses were found to be in the range of 2.89 4.20 eV. The refractive index and polarizability of oxide ion have been calculated by using Lorentz Lorentz relations. The values of refractive index range from 2.13 to 2.42 and those of polarizability of oxide ion range from 6.51×10-24 to 7.80×10-24 cm3.

Eraiah, B.; Bhat, Sudha G.

2007-04-01

365

High upconversion optical gain of Er3+-doped tellurite glass  

NASA Astrophysics Data System (ADS)

The upconversion technique of rare-earth-doped glasses or crystals is a potential route for achieving short-wavelength lasers (SWLs). The optical gain is an important parameter for evaluating lasing medium performance. Therefore, upconversion luminescence in glass with composition of 70TeO2-9PbF2-10AlF3-10BaF2-1Er2O3 was demonstrated, and the small-signal optical gain was measured via an amplified spontaneous emission technique when the sample was excited with a 980 nm laser. It was found that the optical gain was as large as 4.0 dB/cm, thus indicating that this glass may be a good medium for SWLs.

Fu, S. B.; Chen, B. J.; Zhang, J. S.; Li, X. P.; Zhong, H.; Tian, B. N.; Wang, Y. Z.; Sun, M.; Zhang, X. Q.; Cheng, L. H.; Zhong, H. Y.; Xia, H. P.

2014-06-01

366

Electrical conduction in alkali borate glasses; a unique dependence on the concentration of modifier ions  

NASA Astrophysics Data System (ADS)

The electrical conduction of Li2O-B2O3, Na2O-B2O3 and K2O-B2O3 glasses seems, at first sight, to be dominated by the activation energy. Regardless of the size of the alkali ion, there is a unique dependence of conductivity, at a certain temperature, on the alkali-alkali distance and thus on N (the number of ions per cm3). The linear dependence of log? on N-3/2 for all types of alkali ions reveals that N is the basic parameter that determines the conductivity at a certain temperature. A derived semi-empirical relation can be used to calculate the conductivity as a function of N and temperature.

Doweidar, H.; Moustafa, Y. M.; El-Damrawi, G. M.; Ramadan, R. M.

2008-01-01

367

Evaluation of the proliferation and differentiation behaviors of mesenchymal stem cells with partially converted borate glass containing different amounts of strontium in vitro.  

PubMed

The objective of this study was to examine the proliferation and differentiation behaviors of different compositions of strontium-containing (from 0-12 mol%) borate glasses with mesenchymal stem cells (MSCs). The Cell Counting Kit-8 (CCK-8) assay revealed that after three days of culturing, the 6Sr group had the highest cell growth rate. Analysis of cell morphology revealed that cells proliferated well near the particles of the samples in all the groups on day 3. On day 7, cells in the 6Sr group demonstrated a higher proliferation rate than other 4 groups under the microscope. When performing the Live-Dead staining experiment, the 6Sr group had the least number of dead cells. Total DNA qualification indicated that the 6Sr group had a statistically higher concentration compared with the remaining groups. It was found that on day 7, compared with the 0Sr group, the core binding factor ?1 (Cbfa1) mRNA expression level was significantly higher in the 6Sr, 9Sr and 12Sr groups. On day 14, compared with the 0Sr group, the bone sialoprotein (BSP) mRNA level was significantly higher in the 6Sr group. Additionally, on day 21, the 6Sr and 9Sr groups demonstrated higher osteocalcin (OCN) mRNA expression levels compared with the 0Sr group. In the alkaline phosphatase (ALP) activity test, on day 21, the 6Sr group presented a higher activity than the 0Sr group. Further, the number of mineralized nodules per unit in MSCs was measured by Alizarin Red S staining. The results showed that the 6Sr and 9Sr groups had the greatest number of mineralized nodules. Therefore, it could be concluded that borate glasses containing strontium oxide of 0, 3, 6, 9 and 12 mol% demonstrate a significant level of proliferation when interacting with MSCs. The borate glass containing 6 mol% strontium oxide had the greatest level of proliferation when cultured with MSCs. The borate glass containing 6 and 9 mol% strontium oxide facilitated an improved bone formation ability compared with the remaining two compositions. PMID:23446964

Zhu, Yi; Ouyang, Yuanming; Chang, Yi; Luo, Congfeng; Xu, Jun; Zhang, Changqing; Huang, Wenhai

2013-04-01

368

Rare-earth doped transparent nano-glass-ceramics: a new generation of photonic integrated devices  

Microsoft Academic Search

We report on optical properties and prospect applications on rare-earth doped oxyfluoride precursor glass and ensuing nano-glass-ceramics. We find out the spectral optical gain of the nano-glass-ceramics and show that its flatness and breadth are advantageous as compared to contemporary used erbium doped optical amplifiers. We present the possibility of flat gain cross-section erbium doped waveguide amplifiers as short 'chip',

Vicente Daniel Rodríguez-Armas; Victor K. Tikhomirov; Jorge Méndez-Ramos; Angel C. Yanes; Javier Del-Castillo; David Furniss; Angela B. Seddon

2007-01-01

369

Magnetic resonance studies on radiation-induced point defects in mixed oxide glasses. I. Spin centers in B{sub 2}O{sub 3} and alkali borate glasses.  

SciTech Connect

Radiation-induced spin centers in vitreous boron trioxide and alkali borate glasses were studied using pulsed electron paramagnetic resonance (EPR). It is shown that electrons and holes in these glasses are trapped on valence alternation defects, undercoordinated oxygen (holes) and overcoordinated oxygen (electrons). The local environment around these defects has major effect on spin parameters of the corresponding spin centers. The electronic and atomic structure of spin-1/2 centers and their diamagnetic precursors is analyzed using semiempirical and ab initio calculations.

Shkrob, I. A.; Tadjikov, B. M.; Trifunac, A. D.; Chemistry

2000-02-01

370

Laser ablation of silicate glasses doped with transuranic actinides  

SciTech Connect

Direct sampling laser ablation plasma mass spectrometry (DS-LAMS) was applied to silica glasses doped with {sup 237}Np, {sup 242}Pu or {sup 241}Am using a unique instrument recently installed into a transuranic glovebox. The primary goal was to assess the utility of mass spectrometry of directly ablated ions for facile evaluation of actinide (An) constituents of silicate glass immobilization matrices used for encapsulation of radionuclides. The instrument and general procedures have been described elsewhere. Three high-purity silicate glasses prepared by a sol-gel process (SG) and one conventional high-temperature (HT; melting point {approx} 1,450 C) borosilicate glass were studied. These glasses comprised the following constituents, with compositions expressed in mass percentages: Np-HT {approx} 30% SiO{sub 2} + 6% B{sub 2}O{sub 3} + 3% BaO + 13% Al{sub 2}O{sub 3} + 10% PbO + 30% La{sub 2}O{sub 3} + 8% {sup 237}NpO{sub 2}; Np-SG {approx} 70% SiO{sub 2} + 30% {sup 237}NpO{sub 2}; Pu-SG {approx} 70% SiO{sub 2} + 30% {sup 242}PuO{sub 2}; Am-SG {approx} 85% SiO{sub 2} + 15% {sup 241}AmO{sub 2}.

Gibson, J.K.; Haire, R.G.

1998-10-01

371

Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation.  

PubMed

In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects. PMID:20540099

Fu, Qiang; Rahaman, Mohamed N; Bal, B Sonny; Bonewald, Lynda F; Kuroki, Keiichi; Brown, Roger F

2010-10-01

372

Conversion of melt-derived microfibrous borate (13-93B3) and silicate (45S5) bioactive glass in a simulated body fluid.  

PubMed

Microfibrous bioactive glasses are showing a considerable capacity to heal soft tissue wounds, but little information is available on the mechanism of healing. In the present study, the conversion of microfibrous borate bioactive glass (diameter = 0.2-5 ?m) with the composition designated 13-93B3 (5.5 Na2O, 11.1 K2O, 4.6 MgO, 18.5 CaO, 3.7 P2O5, 56.6 B2O3 wt%) was evaluated in vitro as a function of immersion time in a simulated body fluid (SBF) at 37 °C using structural and chemical techniques. Silicate 45S5glass microfibers (45 SiO2, 24.5 Na2O, 24.5 CaO, 6 P2O5 wt%) were also studied for comparison. Microfibrous 13-93B3 glass degraded almost completely and converted to a calcium phosphate material within 7-14 days in SBF, whereas >85 % of the silica remained in the 45S5 microfibers, forming a silica gel phase. An amorphous calcium phosphate (ACP) product that formed on the 13-93B3 microfibers crystallized at a slower rate to hydroxyapatite (HA) when compared to the ACP that formed on the 45S5 fibers. For immersion times >3 days, the 13-93B3 fibers released a higher concentration of Ca into the SBF than the 45S5 fibers. The fast and more complete degradation, slow crystallization of the ACP product, and higher concentration of dissolved Ca in SBF could contribute to the capacity of the microfibrous borate 13-93B3 glass to heal soft tissue wounds. PMID:23233025

Liu, Xin; Rahaman, Mohamed N; Day, Delbert E

2013-03-01

373

Mode-locking of neodymium lasers by glasses doped with PbS nanocrystals  

Microsoft Academic Search

Nonlinear optical absorption properties of silicate glasses doped by the PbS nanocrystals were investigated by means of the picosecond pump-probe absorption spectroscopy and absorption bleaching technique. The glass samples were used as saturable absorbers for passive mode-locking of Nd?:?YAG and Nd?:?glass lasers. Application of the PbS doped glass together with the active mode-locking and laser cavity quality control enabled the

A. Dementjev; V. Gulbinas; L. Valkunas; I. Motchalov; H. Raaben; A. Michailovas

2003-01-01

374

Population dynamics in Er3+-doped fluoride glasses  

NASA Astrophysics Data System (ADS)

A detailed study of the energy-transfer processes in Er3+: flouride glasses with doping concentrations of 0.2-18 mol % is presented. Fluorescence wave forms for 11 erbium transitions were measured under 802-nm, 1.5-?m, 975-nm, 520-nm, and 403-nm excitation from a high-energy short-pulse source. The analysis of these data provided a physical understanding of the processes responsible for the temporal behavior of the populations of a large number of energy levels. A comprehensive nine-level rate-equation model of the Er3+ population dynamics in these fluoride glasses is developed. The model performs well in predicting the observed fluorescence behavior of the main fluorescing lines under all pumping conditions. The modeling process allowed 14 ion-ion energy-transfer processes that are important for the population dynamics in these fluoride glasses to be identified and their rate constants obtained. Noticeably, the inclusion of seven three-ion processes was found necessary in order to obtain good fits to the experimental fluorescence wave forms. It was also found that some three-ion processes have a significant effect on the population dynamics of the levels even in lower doping concentrations.

Bogdanov, V. K.; Booth, D. J.; Gibbs, W. E.; Javorniczky, J. S.; Newman, P. J.; Macfarlane, D. R.

2001-05-01

375

Pr 3+-doped ZBLA fluoride glasses for visible laser emission  

NASA Astrophysics Data System (ADS)

Praseodymium doped Fluoride glasses were studied in order to fabricate compact solid state laser sources emitting in the visible range for lighting application and for quantum information processing. The objective of this study is focused on red, green and orange emissions. ZBLA bulk glasses (57%ZrF 4 - 34%BaF 2 - (5 - x)%LaF 3 - 4%AlF 3 - x%PrF 3) have been synthesized under dry argon atmosphere. Physicochemical and optical properties such as density, glass transition temperature, composition, transmission and refractive index have been investigated. Spectroscopic studies have been performed to optimize the rare earth doping level in order to reach the best compromise respecting a good optical quality, a highest lifetime and efficient emission intensity at 635, 605 and 520 nm. Spectroscopic measurements have been carried out on bulk samples with Pr 3+ concentrations ranging from 0.1 to 3 mol% and first characterizations of ion exchanged Pr: ZBLA waveguides are reported.

Olivier, Melinda; Pirasteh, Parastesh; Doualan, Jean-Louis; Camy, Patrice; Lhermite, Hervé; Adam, Jean-Luc; Nazabal, Virginie

2011-05-01

376

Optical properties of Dy 3+-doped phosphate and fluorophosphate glasses  

NASA Astrophysics Data System (ADS)

Optical properties of Dy 3+-doped phosphate (P 2O 5 + K 2O + BaO + Al 2O 3) and fluorophosphate (P 2O 5 + K 2O + BaO + BaF 2 + Al 2O 3) glasses have been investigated. The observed bands in absorption spectra of 1.0 mol% Dy 3+-doped glasses have been assigned and analyzed using the parametric free-ion Hamiltonian model. Judd-Ofelt (JO) intensity parameters have been obtained from the optical absorption spectra. The sensitiveness of the ?2 JO parameter to the hypersensitive transition has been demonstrated. Using these JO parameters radiative properties of some of the excited states of Dy 3+ ions have been calculated. A strong yellow emission was observed from the 4F 9/2 ? 6H 13/2 transition of Dy 3+ ions in these glasses. The peak stimulated emission cross-section for the 4F 9/2 ? 6H 13/2 transition is found to be comparable with those of other Dy 3+: systems. The decay curves of the 4F 9/2 level have been measured and are found to deviate from exponential nature with increase in Dy 3+ ions concentration. The non-exponential decay curves have been fitted with the Inokuti-Hirayama model which revealed that dipole-dipole mechanism is responsible for the energy transfer processes through Dy 3+-Dy 3+ interactions.

Babu, S. Surendra; Babu, P.; Jayasankar, C. K.; Tröster, Th.; Sievers, W.; Wortmann, G.

377

Er-doped and Er, Yb co-doped oxyfluoride glasses and glass-ceramics, structural and optical properties  

NASA Astrophysics Data System (ADS)

The selected glasses and glass-ceramics pertinent to following chemical composition in mol%:48%SiO 2-11%Al 2O 3-7%Na 2O-10%CaO-10%PbO-11%PbF 2-3%ErF 3 and 48%SiO 2-11%Al 2O 3-7%Na 2O-10%CaO-10%PbO-10%PbF 2-1%ErF 3-3%YbF 3 have been manufactured from high purity components (Aldrich) at 1450 °C in normal atmosphere. Glass optical fibers were successfully drawn. Subsequently they were subject to the heat-treatment at 700 °C in various time periods. The preceding differential thermal analysis (DTA) studies allowed estimating both the fiber drawing temperature and the controlled crystallization temperature of glass fibers. It has been observed that the controlled heat-treatment of oxyfluoride glass fibers results in the creation of Pb 5Al 3F 19, Er 4F 2O 11Si 3 and Er 3FO 10Si 3 crystalline phases. The identified phases were characterized by X-ray powder diffraction (XRD) and confirmed by selected area electron diffraction (SAED). The fibers consist of mixed amorphous-crystalline microstructure with nano-crystals of size even below 10 nm distributed in the glassy host. Their morphology was investigated applying high-resolution transmission electron microscopy. Optical properties and excited state relaxation dynamics of optically active ions (Er 3+, Yb 3+) in glass and glass-ceramics have been studied. Based on absorption spectra the Judd-Ofelt analysis was carried out. The main attention was directed to NIR luminescence at. 1.6 ?m related to 4I 13/2 ? 4I 15/2 Er 3+ and less effective emission associated with 4I 11/2 ? 4I 15/2 Er 3+ and 2F 5/2 ? 2F 7/2 Yb 3+ transitions. The dissimilar spectroscopic properties have been revealed for glasses and glass-ceramic samples, respectively. The reduction of emission linewidth at 1.6 and 1.0 ?m combined with substantial increase of 4I 13/2 lifetimes of erbium in glass-ceramics appear to be evidences that Er 3+ ions are accommodated in crystalline phases. The structural and optical characteristics of oxyfluoride glass-ceramic fibers indicate that these optical systems may be considered as promising materials for Er-doped optical amplifiers operating within third telecommunication window.

Lisiecki, Rados?aw; Augustyn, El?bieta; Ryba-Romanowski, Witold; ?elechower, Micha?

2011-09-01

378

Nd-doped phosphate glass microstructured optical fiber laser  

NASA Astrophysics Data System (ADS)

We experimentally demonstrated a single-mode laser at 1056 nm with Nd-doped phosphate glass microstructured optical fiber (MOF), which was fabricated with conventional stack-and-draw method. The laser action was observed from a Fabry-Perot cavity formed by placing two dichroic mirrors of ˜100 and 85% reflectivity, to the two end facets of MOF. Pumped by CW laser diodes (LDs) at 808 nm, the MOF laser yielded a maximum output power of 8.5 mW and a slope efficiency of 2%.

Zhang, G.; Luo, F. F.; Liu, X. F.; Dong, G. P.; Zhang, Q.; Lin, G.; Zhou, Q. L.; Qiu, J. R.; Hu, L. L.; Chen, D. P.

2010-06-01

379

Energy upconversion in holmium doped lead-germano-tellurite glass  

SciTech Connect

Holmium doped lead-germano-tellurite glass was prepared by the melt quenching technique. The Judd-Ofelt intensity parameters were estimated as {Omega}{sub 2}=7.6x10{sup -20}, {Omega}{sub 4}=12.9x10{sup -20}, and {Omega}{sub 6}=2.5x10{sup -20} cm{sup 2}. Radiative transition probabilities and lifetimes were also determined for some of the levels. Room temperature upconversion emissions have been observed from Ho{sup 3+} at 497 nm under 532 nm laser excitation, and at 557 and 668 nm under 762 nm laser excitation. The upconversion emission mechanisms were found to be due to a step wise excitation process. Upconversion emission intensity enhanced in a heat treated glass.

Kamma, Indumathi; Reddy, B. Rami [Department of Physics, Alabama A and M University, P.O. Box 1268, Normal, Alabama 35762 (United States)

2010-06-15

380

Investigation of nonlinear properties of CdS-doped glasses  

NASA Astrophysics Data System (ADS)

The dynamics of photodarkening and transient absorption in commercial CdS-doped filter glass Asahi Y45 has been investigated at room temperature using pump and probe spectroscopy. The fresh spot of the sample was irradiated by pump pulse with the wavelength of 355 nm above the band gap and the probing was done at different wavelengths (1064, 760, and 469 nm). Influence of exposure as well as probe wavelength on dynamics of carriers has been investigated. The long lived photoinduced absorption dynamics corresponding to the higher probe photon energy illustrates the dominant contribution of the trapping states from the glass matrix. A simple model has been presented to understand the photoinduced carrier dynamics. The amplitude of differential absorbance as well as the photodarkening dynamics connected to the interior states are found to be in good agreement with the Drude's free electron model.

Santhi, S.; Trojánek, F.

2005-03-01

381

Development of continuous glass melting for production of Nd-doped phosphate glasses for the NIF and LMJ laser systems  

NASA Astrophysics Data System (ADS)

The NIF and LMJ laser systems require about 3380 and 4752 Nd-doped laser glass slabs, respectively. Continuous laser glass melting and forming will be used for the first time to manufacture these slabs. Two vendors have been chosen to produce the glass: Hoya Corporation and Schott Glass Technologies. The laser glass melting systems that each of these two vendors have designed, built and tested are arguably the most advanced in the world. Production of the laser glass will begin on a pilot scale in the fall of 1998.

Campbell, Jack H.; McLean, M. J.; Hawley-Fedder, Ruth A.; Suratwala, Tayyab I.; Ficini-Dorn, G.; Trombert, Jean-Hugues

1999-07-01

382

Spectral Investigations on Ho3+ Doped Mixed Alkali Chloroborate Glasses  

NASA Astrophysics Data System (ADS)

The optical absorption and emission spectra of two different Ho3+ doped mixed alkali chloroborate glasses have been studied in the ultraviolet-visible near-infrared regions. Various spectroscopic parameters like Racah (E1, E2, and E3), spin orbit (?4f), and configuration interaction (?) parameters have been calculated. From the measured spectral intensities of the various absorption bands of Ho3+ ion, the Judd-Ofelt intensity parameters (?2, ?4, and ?6) have been evaluated and covalency was studied as a function of x in the glass matrices. Using these parameters, radiative transition probabilities, radiative lifetimes, branching ratios, and integrated absorption cross-sections have been calculated and reported for certain excited states of Ho3+ ion. From the emission spectra, stimulated emission cross-sections are determined for the emission transitions, 5F4, 5S2 ? 5I8, and 5F5 ? 5I8 in these two mixed alkali chloroborate glasses. An attempt has been made to throw some light on the environment of Ho3+ ions in these glass systems by studying the variation in various spectroscopic parameters.

Venkateswarlu, C.; Ratnakaram, Y. C.; Seshadri, M.; Naidu, D. Thirupathi

2011-12-01

383

Highly doped phosphate glass fibers for fiber lasers and amplifiers with applications  

Microsoft Academic Search

Rare-earth doped fiber lasers and fiber amplifiers are highly attractive due to their efficiency, compactness, and, particularly, for their potential to various applications including communication systems, biomedical equipment, materials processing, LIDAR, and fiber-optic sensing. At the heart of these devices is the active fiber - most commonly based on silica host glass. However, the ability to dope silica glass fibers

Arturo Chavez-Pirson

2010-01-01

384

Spectroscopic studies on Fe 3+ and Mn 2+ doped SrB 4O 7 glasses  

NASA Astrophysics Data System (ADS)

EPR and optical absorption studies on Fe 3+ and Mn 2+ doped strontium tetraborate (SrB 4O 7) glasses are carried out at room temperature. The EPR spectrum of the Fe 3+ doped glass consists of signals with g-values 9.04, 4.22 and 2.04, whereas the EPR spectrum of Mn 2+ doped glass exhibits a characteristic hyperfine sextet around g=2.0. The spectroscopic analyses of the obtained results confirmed distorted octahedral site symmetry for the Fe 3+ and Mn 2+ impurity ions. Crystal field and Racah parameters evaluated from optical absorption spectra are: Dq=790, B=700 and C=3000 cm -1 for Fe 3+doped glass and Dq=880, B=700 and C=2975 cm -1 for Mn 2+ doped glass.

Prakash, I. N.; Babu, B.; Venkata Reddy, Ch.; Narayana Murty, P.; Reddy, Y. P.; Sambasiva Rao, P.; Ravikumar, R. V. S. S. N.

2011-09-01

385

Thermally Induced Nanostructures in Samarium-Doped Glass Ceramics for X-Ray Sensor Applications  

NASA Astrophysics Data System (ADS)

There is much interest in various glass-ceramics doped with rare-earth (RE) metals for x-ray storage phosphor and/or x-ray scintillator applications for potential use in high resolution x-ray imaging. The phosphor and scintillator properties of these glass ceramics depend on the formation of RE embedded nanocrystals in their structure. The heat treatment and annealing of the starting RE-doped glasses is critically important to the formation and control of the glass ceramic nanocrystals. We have studied the thermal and photoluminescence properties of Sm-doped fluorochlorozirconate glass ceramics. We selected useful host compositions and appropriate heat treatment and annealing procedures needed to grow the required RE-doped nanocrystals in a glass matrix for sensor applications.

Tonchev, Dan; Belev, G.; Koughia, C.; Panigrahi, S.; Varoy, C.; Edgar, A.; Kasap, S. O.

386

Formation of nanoclusters in silver-doped glasses in wet atmosphere  

Microsoft Academic Search

Thermal stability of silver ions in silicate glasses in dry and wet (0.5 - 50% of water content) atmosphere under elevated (160-230 °C) temperature is studied. The glass is doped with silver using silver-to-sodium ion exchange procedure conventionally used for the formation of optical waveguides. It is found that the isothermal annealing of glasses doped with Ag+ ions in a

Yu Kaganovskii; E. Mogilko; A. A. Lipovskii; M. Rosenbluh

2007-01-01

387

Synthesis and characterization of low-melting scintillating glass doped with organic activator  

Microsoft Academic Search

New colliders for high-energy physics studies require scintillators with short decay time, high density, good radiation hardness and low cost. It is possible to make glass scintillators that can meet these requirements by doping organic scintillating activators into an inorganic glass host. In this research, p-Terphenyl as the activator is doped into lead–tin-fluorophosphate glasses. There is no detectable change of

Hongsheng Zhao; Wancheng Zhou; Dongmei Zhu; Jingbo Wu

2000-01-01

388

Luminescent properties of Tb3+ and Gd3+ ions doped aluminosilicate oxyfluoride glasses.  

PubMed

Tb(3+) and Gd(3+) ions doped lithium-barium-aluminosilicate oxyfluoride glasses have been prepared. The transmission, emission and excitation spectra were measured. It has been found that those Tb(3+)-doped lithium-barium-aluminosilicate oxyfluoride glasses exhibit good UV-excited luminescence. The luminescence intensity of Tb(3+) ion increases for those (Tb(3+), Gd(3+))-codoped glasses. Energy transfer process from Gd(3+) ion to Tb(3+) ion is indicated. PMID:21831699

Zuo, Chenggang; Lu, Anxian; Zhu, Ligang; Zhou, Zhihua; Long, Woyun

2011-11-01

389

Doping of ZnO nanowires using phosphorus diffusion from a spin-on doped glass source  

NASA Astrophysics Data System (ADS)

In this article, we report on ZnO nanowires that were phosphorus doped using a spin on dopant glass deposition and diffusion method. Photoluminescence measurements suggest that this process yields p-doped ZnO. The spatial location of P atoms was studied using x-ray near-edge absorption structure spectroscopy and it is concluded that the doping is amphoteric with P atoms located on both Zn and O sites.

Bocheux, A.; Robin, I. C.; Bonaimé, J.; Hyot, B.; Kolobov, A. V.; Mitrofanov, K. V.; Fons, P.; Tominaga, J.; Tamenori, Y.; Feuillet, G.

2014-05-01

390

Glass-forming ability and chemical stability of magneto-optical glass heavily doped with rare earth oxide  

Microsoft Academic Search

The glass-forming region of B2O3-Al2O3-SiO2 (BAS) glass heavily doped with rare earth oxides was investigated by an effective method, and the chemical stability was\\u000a investigated by powder method. Influences of rare earth oxides on the glass-forming ability and the chemical stability of\\u000a the BAS glass were also discussed. The experimental results show that the BAS glass-forming region expands firstly with

Hairong Yin; Chunxiang Zhang; Liying Liu; Guoping Chen; Baojun Tang

2009-01-01

391

Nonlinear optical properties of commercial and experimental semiconductor-doped glasses  

Microsoft Academic Search

The nonlinear optical properties, more specifically the Kerr nonlinearity, of commercial semiconductor-doped glasses have been extensively studied. The nonlinear mechanism is mainly bulk-like since no sizeable quantum confinement effect was observed in these glasses. Quantum confinement is however clearly exhibited by experimental glasses containing smaller particles. For CdSSe, phonon broadening is observed to play an important role.

D. Ricard; P. Roussignol; C. Flytzanis; N. Neuroth

1989-01-01

392

Advances in terbium-doped, lithium-loaded scintillator glass development  

Microsoft Academic Search

Terbium-doped, lithium-loaded glass scintillator samples were fabricated for improvement in neutron detection capability and light output. Samples were tested with both UV and neutron excitation. The improved glass yielded approximately twice as many scintillation photons per absorbed neutron as the original glass.

Garry B. Spector; Tom McCollum; Alexander R. Spowart

1993-01-01

393

Yb3+-ion-doped glass with high stimulated emission cross-section at near-IR  

NASA Astrophysics Data System (ADS)

In this paper the glass formation, physical and spectroscopic properties of phospho-tellurate and germano- tellurate glasses are systematically studied. Yb3+- doped laser glasses with high stimulated emission cross- section are discussed.

Deng, Peizhen; Jiang, Chun; Yin, Hongbing; Gan, Fuxi

1998-09-01

394

Novel rare earth doped tellurite glasses for fiber lasers in the 2-micron wavelength region  

NASA Astrophysics Data System (ADS)

In this paper Tm-doped tellurite glasses (75TeO II-20ZnO-5 Na IIO, mol%) were prepared and characterized, and codoping with Yb was investigated in order to improve pump efficiency and wavelength emission range. Emission spectra and lifetime measurements were obtained by pumping Tm-doped tellurite glasses at 800 nm and Yb-Tm co-doped tellurite glasses at 980 nm, thus exploiting the Yb-Tm energy transfer mechanism. Highly Yb-doped Tm-tellurite glasses were investigated (Yb IIO 3 concentrations up to 5 wt%) and an increase in 3F 4 lifetime with Yb IIO 3 concentrations higher than 3% was observed. This showed that high amounts of Yb do not affect lifetime of the metastable state, thus allowing investigation of lasers in this range of doping concentrations.

Milanese, Daniel; Vota, Monica; Liao, Guihua; Ferraris, Monica; Coluccelli, Nicola; Taccheo, Stefano

2007-03-01

395

Photoluminescence of Pr3+-, Dy3+- and Tm3+-doped transparent nanocrystallized KNbGeO5 glasses  

Microsoft Academic Search

In this paper, we present the photoluminescence properties of Pr3+-, Dy3+- and Tm3+-doped potassium-niobium-germanate glasses and glass ceramics. From the x-ray diffraction measurement, the glass structure was established. These glasses have shown strong absorption bands in the near-infrared region. Compared with Pr3+-, Dy3+- and Tm3+-doped glasses, their respective glass ceramics have shown stronger emissions due to the presence of the

G. Lakshminarayana; Jianrong Qiu; M. G. Brik; I. V. Kityk

2008-01-01

396

Upconversion dynamics in Er 3+-doped fluoroindate glasses  

NASA Astrophysics Data System (ADS)

The mechanisms and dynamics of the upconversion emissions in Er 3+-doped fluoroindate glasses by exciting in the range from 955 to 975 nm have been investigated. The upconversion emissions observed at 545 and 660 nm have been analysed studying their dependence on excitation intensity and Er 3+ concentration. Temperature dependence of the upconversion efficiency for these emissions has been measured in the range from 10 to 295 K. The temporal evolution of the 545 nm upconversion emission has been obtained as a function of the wavelength of the pulsed excitation. From the analysis of these measurements with a proposed model, the relative weight of excited state absorption and energy transfer has been obtained.

Martín, I. R.; Vélez, P.; Rodríguez, V. D.; Rodríguez-Mendoza, U. R.; Lavín, V.

1999-05-01

397

Holographic Image Storage in Eu 3 +-Doped Alkali Aluminosilicate Glasses  

NASA Astrophysics Data System (ADS)

We demonstrate that holographic information can be stored in Eu3 +-doped alkali aluminosilicate glasses. The holograms were developed by a two-beam mixing configuration with a write-beam wavelength (465.8 nm) corresponding to the7F0 5D0 transition of the Eu3 + ions. The images were reconstructed either with the wavelength used to record them or with wavelengths below this transition (543.5 and 632.8 nm). We stored clear holographic images using a total writing power of 5 mW and an exposure time of 20 s. In addition, clear holograms were recorded with an exposure time of 200 ms when 100 mW of the writing power was used. The exposure time and the writing power required to obtain clear holographic images are dependent on the Eu3 +concentration.

Hamad, Abdulatif Y.; Wicksted, James P.

2001-04-01

398

[Investigation on spectroscopic properties of Yb3+ -doped laser glasses].  

PubMed

Yb3+ -doped borosilicate glasses were prepared at high tempreture. The absorption spectra and fluorescence spectra were measured at room temperature. The integrated absorption cross section, stimulated emission cross section and fluorescent time were calculated. The results showed that the main peak wavelength was 975.15 nm in absorption spectra with one subpeak near 937.17 nm; emission peak was at 977.15 nm in fluorescence spectra with one subpeak near 997.42 nm; with increasing the sample thickness from 0.5 to 5 mm, luminescence intensity became greater, and the peak shifted to longer wavelength from 995.79 to 999.02 nm. The effective line width of fluorescence increased from 34.64 to 54.50 nm; Fluorescence lifetime decreased from 1.04 to 1.00 ms. PMID:17205719

Li, Wei-nan; Ding, Guang-lei; Lu, Min; Xiang, Li-bin

2006-10-01

399

Optical characterization of Er-doped glasses for solar-pumped laser applications  

NASA Astrophysics Data System (ADS)

Quantum efficiencies of Er3+-doped silicate, phosphate, tellurite and fluoride glasses have been examined under simulated sunlight excitation. The quantum efficiency of the whole emission bands was obtained as about 75 % for fluoride glass and about 2 % for silicate glass. The maximum quantum efficiency of the emission band at 1530 nm was about 35 % for fluoride glass and about 17 % for silicate glass. The product of the stimulated emission cross-section and the emission lifetime ?st?f was about 46×10-24 cm2 sec for fluoride glass and about 54×10-24 cm for silicate glass. These values are about 2-4 times larger than that of Nd-doped glasses.

Suzuki, Takenobu; Iwata, Yasuyuki; Nogata, Kohei; Mizuno, Shintaro; Ito, Hiroshi; Hasegawa, Kazuo; Ohishi, Yasutake

2013-03-01

400

Light emission of Cu+ doped porous silica glass for volumetric three-dimensional solid state display  

NASA Astrophysics Data System (ADS)

Cu-doped nanoporous silica glass was prepared and broadband upconversion luminescence was observed when excited with a 800 nm femtosecond laser. The optical properties of the Cu-doped nanoporous silica glass were investigated by absorption, steady state excitation and emission, luminescence decay and time-resolved spectroscopy. The analysis of the upconversion mechanism indicates that three-photon absorption is responsible for the visible luminescence. A three-dimensional solid state display was also demonstrated and the full colorization of a volumetric three-dimensional solid state display could be made possible by designing and controlling the combination of doping species in the nanoporous silica glass.

Zhou, Shifeng; Zhu, Bin; Lin, Geng; Yang, Hucheng; Xu, Shiqing; Wang, Zhiyu; Qiu, Jianrong

2007-12-01

401

Improved omnidirectional reflectors in chalcogenide glass and polymer by using the silver doping technique  

NASA Astrophysics Data System (ADS)

We describe the fabrication and characterization of omnidirectional reflectors based on silver-doped chalcogenide glass and polymer. We deposited periodically alternating layers of thermally evaporated Ge33As12Se55 chalcogenide glass, sputtered silver, and spun-cast polyamide-imide polymer. The silver was subsequently dissolved into each adjacent chalcogenide glass layer, either by exposing the multilayer to visible light (photodoping) or by heating the sample. The resultant silver concentration within the chalcogenide glass layers is estimated to be ~20 at. %. Silver doping red-shifts the band edge of the glass, and produces an increase of ~0.3-0.4 in the refractive index. The glass retains good transparency in the near infrared after doping, and the technique enables the omnidirectional bandwidth to be increased from ~100 nm to ~200 nm in the 1550 nm wavelength region.

Clement, Thomas; Ponnampalam, N.; Nguyen, H. T.; Decorby, R. G.

2006-03-01

402

Scintillating glass doped with organic activator pTP and\\/or POPOP  

Microsoft Academic Search

Two organic activators, p-TP(p-terphenyl) and POPOP (1,4-bis(5-phenyloxazol-2-yl) benzene), which are normally used to prepare the scintillating plastic, were doped in tin fluorephosphate glasses to develop a serial of scintillating glasses with different concentrations. The fluorescence spectra and the transmission spectra of some scintillating glass were explored and the actual concentration organic in scintillating glass was estimated by comparing the extracted

Dongmei Zhu; Fa Luo; Hongsheng Zhao; Wancheng Zhou

2006-01-01

403

Study on the laser-induced darkening in Nd-doped laser glasses  

Microsoft Academic Search

Laser induced darkening in the soda-lime silicate (15Na2O·15CaO·70SiO2) based glass and type N31 barium metaphosphate Ba(PO3)2 based glass were studied by exposing the glass samples in frequency-quadrupled Nd:YAG (266 nm, 5 ns) laser and Ti:Sapphire (800 nm, 120 fs) laser. Both types of the glasses were doped with Nd2O3 at doping levels less than 3 wt%. Hole center HC1 formed

Qinling Zhou; Lei Xu; Liying Liu; Wencheng Wang; Congshan Zhu; Fuxi Gan

2004-01-01

404

Influence of CeO2 addition on the electrical and optical properties of lithium borate glasses  

NASA Astrophysics Data System (ADS)

The glass series with general formula 15 Li2O-(85-X) B2O3-X CeO2 was prepared using the conventional melt quench technique. The electrical conductivity, the optical properties and the coefficient of thermal expansion were measured for the prepared glasses. The conductivity of the glasses decreases with the addition of CeO2 because the mobility of Li+ ions and the compactness of the glass structure decrease. The density and the refractive index of the glasses increase, whereas the optical band gap and the radiation length decrease because of the structural changes.

Gedam, R. S.; Ramteke, D. D.

2013-10-01

405

The Verdet constant of Er-doped crystalline YAG and tellurite glass at 1645 nm  

NASA Astrophysics Data System (ADS)

We describe the measurement of the Verdet constant of undoped and Er-doped crystalline YAG and tellurite glass at 1645 nm. The undoped YAG value is compared to those measured using visible light. We show that the paramagnetic nature of Er reduces the Verdet constant but that the decrease is probably not significant for the typical Er doping levels used in Er:YAG or in Er:tellurite-glass mid-IR lasers.

Harris, Lachlan; Ottaway, David; Veitch, Peter J.

2012-02-01

406

Erbium-doped ion-exchanged waveguide lasers in BK7 glass  

Microsoft Academic Search

Ion-exchange in glass is a simple, flexible technique to realize optical fiber-compatible planar waveguide devices. Recently, neodymium-doped waveguide lasers operating at 1060 and 1300 nm have been demonstrated in this technology. Lasers operating at 1540 nm are desirable for telecommunication applications and the authors report for the first time ion-exchanged waveguide lasers in erbium-doped glass emitting at this wavelength. Lasers

T. Feuchter; E. K. Mwarania; J. Wang; L. Reekie; J. S. Wilkinson

1992-01-01

407

Lifetime and cross-relaxation in highly Tm-doped glasses for 2 micron lasers  

NASA Astrophysics Data System (ADS)

In this paper, we present our recent investigation of highly doped Tm3+ tellurite glass. The optical properties of series of tellurite glass samples (75 mol % TeO2 - 20 mol ZnO - 5 mol % Na2O) highly doped with Tm3+ ions were reported and discussed. An exhaustive set of samples from low concentration to very high have been used in this study. Cross relaxation process has been studied and cross-relaxation parameter has been calculated.

Taher, M.; Gebavi, H.; Taccheo, S.; Jousteau, L.; Milanese, D.; Peyghambarian, N.

2011-02-01

408

FLUORESCENCE PROPERTIES OF As2S3 GLASS DOPED WITH RARE-EARTH ELEMENTS  

Microsoft Academic Search

Chalcogenide glasses doped with various rare-earth ions are extensively studied as potential materials for fiber optic amplifiers operating at 1.3 and 1.5 ?m telecommunication windows. The experimental results on optical absorption and photoluminescence of arsenic sulfide glasses and optical fibers doped with rare-earth elements (Pr3+, Sm3+, Er3+ and Dy3+) are presented. Near the absorption edge the rare-earth impurities affect strongly

M. Iovu; A. Andriesh; I. Culeac

409

Photoluminescence in rare-earth doped As2S3 glasses  

Microsoft Academic Search

Chalcogenide glasses doped with various rare-earth ions are extensively studied as potential materials for fiber optic amplifiers operating at 1.3 and 1.5 mum telecommunication windows. The experimental results on optical absorption and photoluminescence of arsenic sulfide glasses and optical fibers doped with rare-earth elements (Pr3+, Sm3+, Er3+ and Dy3+) are presented. Near the absorption edge the rare-earth impurities affect strongly

Mihai S. Iovu; Andrei M. Andriesh; Ion P. Culeac

2005-01-01

410

Transmission and absorption spectra of aluminophosphate-doped glasses with rare-earth ions  

Microsoft Academic Search

Aluminophosphate glasses doped with rare-earth ions have recently attracted a large interest owing to their relevant non-linear optical properties. Until now, all studies were done over the glasses doped with rare-earth ions in which the rare-earth ions were into a vitreous silica matrix. Our study was made as for rare-earth ions into a vitreous aluminophosphate matrix. In the first step,

Rodica Rogojan; Paul E. Sterian; Mihai Elisa

1998-01-01

411

Light emission of Cu+ doped porous silica glass for volumetric three-dimensional solid state display  

Microsoft Academic Search

Cu-doped nanoporous silica glass was prepared and broadband upconversion luminescence was observed when excited with a 800 nm femtosecond laser. The optical properties of the Cu-doped nanoporous silica glass were investigated by absorption, steady state excitation and emission, luminescence decay and time-resolved spectroscopy. The analysis of the upconversion mechanism indicates that three-photon absorption is responsible for the visible luminescence. A

Shifeng Zhou; Bin Zhu; Geng Lin; Hucheng Yang; Shiqing Xu; Zhiyu Wang; Jianrong Qiu

2007-01-01

412

Highly nonlinear near-resonant photodarkening in a thulium-doped aluminosilicate glass fiber.  

PubMed

Permanent photoinduced optical attenuation has been observed in Tm(3+)-doped aluminosilicate glass fibers on exposure to near-resonance mode-locked 1064-nm radiation at 300 K. The rate of this darkening was observed to follow a 4.7 +/- 0.4 power dependence on the 1064-nm intensity. The result shows that absorption of infrared light of moderate intensity can lead to photoionization in rare-earth-doped glass, provided that a multiphoton stepwise excitation channel exists. PMID:19802277

Broer, M M; Krol, D M; Digiovanni, D J

1993-05-15

413

Preparation and optical properties of Bi2S3 microcrystallite-doped glass and thin film  

Microsoft Academic Search

The Bi2S3 microcrystallite doped thin films and glass lumps have been successfully prepared by the sol-gel process, the size of the microcrystallite in glass heated for different times at 400 degree(s)C was decided by the method of HRTEM. The optical transmission valley shifted towards longer wavelengths with longer heat-treatment time at 500 degree(s)C in the Bi2S3 doped thin films, showing

Zhonghong Jiang; Hui Ye

1994-01-01

414

Mid-infrared emission from Dy3+ doped tellurite bulk glass and waveguides  

NASA Astrophysics Data System (ADS)

We present the fabrication and characterisation of Dy3+-doped tellurite glasses and waveguides for applications in the mid-IR. The low phonon energy and large rare-earth ion solubility of tellurite glasses, as well as having infrared transmission ranges up to <5 ?m, make them promising candidates for new mid-IR solid-state laser host materials. This paper presents recent achievements in the fabrication of tellurite glasses, glass characterisation and rare-earth ion spectroscopy which is compared to other glass hosts relevant to the mid-IR such as fluoride glasses. When excited with an 808 nm laser diode source, Dy3+ doped tellurite bulk glasses exhibited very broad fluorescence from the 6H13/2 - 6H15/2 transition which extends from 3 ?m to 3.6 ?m FWHM compared to 2.9 ?m to 3.1 ?m in Dy3+ doped ZBLAN glass. This broad and red-shifted fluorescence band in tellurite glass may find use in LIDAR and sensing applications as it coincides with an atmospheric transmission band, compared to the ~3 ?m emission of Dy3+ doped ZBLAN lasers which is absorbed by atmospheric water.

Richards, Billy D. O.; Teddy-Fernandez, Toney; Jha, Animesh; Binks, David

2012-11-01

415

Effect of 1 MeV electrons on ceria-doped solar cell cover glass  

NASA Technical Reports Server (NTRS)

The effect of 1 MeV electrons on the transmission properties of 1.5-percent ceria-doped solar cell cover glass was studied. Samples of doped and undoped cover glass and synthetic fused silica were irradiated with a total integrated flux of 10 to the 15th power e/sq cm. Wideband transmission and spectral transmission measurements were made before and after irradiation. The results indicate that 1.5-percent ceria-doped cover glass is much less sensitive to radiation induced discoloration than undoped cover glass. Consequently, the glass is comparable to synthetic fused silica when used as a radiation resistant solar cell cover for many space missions.

Haynes, G. A.

1973-01-01

416

Visible emission in Sm3+ and Tb3+ doped phosphate glass excited by UV radiation  

NASA Astrophysics Data System (ADS)

In the article analysis of UV absorption and visible fluorescence of Sm3+ and Tb3+ ions doped phosphate glass with molar composition: 65P2O5 + 8Al2O3 + 10BaO + 17(Na2O + MgO + ZnO) have been investigated. As a result of optical pumping fabricated glass with radiation from a deuterium lamp four luminescence bands were observed near to the wavelength of 600 nm for Sm3+ ions and 550 nm for Tb3+ ions. It was found that larger energy gap between laser and ground levels leads to the strongest emission in the visible range in terbium doped glasses than in glasses doped with samarium ions. Both fabricated glasses are characterized by the ability to selectively detect the radiation in the UV range.

Zmojda, Jacek; Dorosz, Dominik; Kochanowicz, Marcin; Miluski, Piotr; Czajkowski, Karol; Ragin, Tomasz

2013-10-01

417

Quantum efficiency of Nd3+-doped phosphate glass under simulated sunlight  

NASA Astrophysics Data System (ADS)

Nd3+-doped P2O5-Al2O3-K2O-BaO (LHG-8) glasses were prepared and the internal quantum efficiency (QE) of near-infrared emission of the glasses were directly measured with a simulated sunlight source and an 800 nm laser. The stimulated emission cross section (?) and the radiative emission lifetime (?r) were also obtained by Judd-Ofelt analysis. The QE of Nd3+:LHG-8 under the simulated sunlight was as high as 60% at the Nd2O3 concentration of 0.05 mol%, and this value was higher than those of Nd3+-doped oxide glasses, such as borosilicate, silicate, and tellurite glasses. The ??r of LHG-8 was also higher than those of the other Nd3+-doped oxide glasses.

Nogata, Kohei; Suzuki, Takenobu; Ohishi, Yasutake

2013-09-01

418

The double role played by the Gd 2O 3 in the gadolinium-aluminum-borate-bismuthate quaternary glass forming tendency. GdBO 3 crystalline phase  

NASA Astrophysics Data System (ADS)

Glasses and glass-ceramics in the xGd 2O 3·(100 - x)[2Bi 2O 3·B 2O 3·Al 2O 3] system with x = 0, 1, 5, 10, 15, 20, 25, 30, 35, 50 mol% Gd 2O 3 have been prepared by the melt quenching method. The changes of the IR spectral features suggest that the formation of [BO 4] tetrahedra is reduced because the modified [BO 3] units containing one or more B-O-Gd bonds are unable to accept the fourth oxygen. Based on our results, we conclude that the accommodation of the networks with the excess of oxygen is possible by the deformation of Bi-O-Bi linkages, the participation of aluminum atoms as network formers and the intercalation of [BiO 6] and [AlO 4] entities in the [BO 4] chain network. When high Gd 2O 3 content is introduced, more [BO 3] structural units are coupled with gadolinium ions and the accumulation of oxygen can be supported by the formation of new [BO 3] -3 structural units as ortho-borate units. These yield the formation of GdBO 3 crystalline phase which has been confirmed by XRD investigations. Comparing the theoretical and experimental IR spectral characteristic features, we conclude that the prediction of the structural data is good.

Rada, S.; Culea, M.; Rada, M.; Pascuta, P.; Maties, V.; Culea, E.

2009-11-01

419

Er3+-doped Multicomponent Silicate Glass Planar Waveguides Prepared by Sol-Gel Processing  

Microsoft Academic Search

Erbium doped silica-titania planar waveguides, co-doped with ytterbium and aluminum, have been prepared by sol-gel processing, using multilayer spin-coating deposition on silicon or silica glass substrates. The Er3+ doping level varied between 0 and 2 at.%, while Yb3+ varied from 0 to 3 at.%. Aluminum was incorporated up to 15 at.% Al and it was found to have no significant

Rui M. Almeida; Xin Min Du; Denis Barbier; Xavier Orignac

1999-01-01

420

Radiation damage induced by ? irradiation on Ce 3+ doped phosphate and silicate scintillating glasses  

Microsoft Academic Search

The effect of ? irradiation on the optical properties of Ce3+-doped phosphate and silicate glasses is studied in the 1–250Gy dose range. Results are discussed by taking into account the possible dependence of radiation-induced effects on the composition of the glass matrix.

S Baccaro; A Cecilia; E Mihokova; M Nikl; K Nitsch; P Polato; G Zanella; R Zannoni

2002-01-01

421

Radiation damage induced by \\/gamma irradiation on Ce3+ doped phosphate and silicate scintillating glasses  

Microsoft Academic Search

The effect of \\/gamma irradiation on the optical properties of Ce3+-doped phosphate and silicate glasses is studied in the 1-250Gy dose range. Results are discussed by taking into account the possible dependence of radiation-induced effects on the composition of the glass matrix.

S. Baccaro; A. Cecilia; E. Mihokova; M. Nikl; K. Nitsch; P. Polato; G. Zanella; R. Zannoni

2002-01-01

422

Properties of Laser-Induced Gratings in Eu-Doped Glasses.  

National Technical Information Service (NTIS)

The properties of permanent, laser-induced gratings were studied in Europium (3+) -doped glasses. These gratings are associated with a structural modification of the glass host in the local environment of the Eu(3+) ions, and we have investigated the effe...

E. G. Behrens F. M. Durville R. C. Powell D. H. Blackburn

1989-01-01

423

Fluoride-modified electrical properties of lead borate glasses and electrochemically induced crystallization in the glassy state  

SciTech Connect

Lead fluoroborate glasses were prepared by the melt-quenching technique and characterized in terms of (micro)structural and electrical properties. The study was conducted on as prepared as well as temperature- and/or electric field-treated glass samples. The results show that, in the as-prepared glassy-state materials, electrical conductivity improved with increasing the PbF{sub 2} glass content. This result involves both an increase of the fluoride charge carrier density and, especially, a decrease of the activation energy from a glass structure expansion improving charge carrier mobility. Moreover, for the electric field-treated glass samples, surface crystallization was observed even below the glass transition temperature. As previously proposed in literature, and shown here, the occurrence of this phenomenon arose from an electrochemically induced redox reaction at the electrodes, followed by crystallite nucleation. Once nucleated, growth of {beta}-PbF{sub 2} crystallites, with the indication of incorporating reduced lead ions (Pb{sup +}), was both (micro)structurally and electrically detectable and analyzed. The overall crystallization-associated features observed here adapt well with the floppy-rigid model that has been proposed to further complete the original continuous-random-network model by Zachariasen for closely addressing not only glasses' structure but also crystallization mechanism. Finally, the crystallization-modified kinetic picture of the glasses' electrical properties, through application of polarization/depolarization measurements originally combined with impedance spectroscopy, was extensively explored.

M'Peko, Jean-Claude; Souza, Jose E. de; Rojas, Seila S.; Hernandes, Antonio C. [Grupo Crescimento de Cristais e Materiais Ceramicos (GCCMC), Instituto de Fisica de Sao Carlos (IFSC), Universidade de Sao Paulo - USP, C. Postal: 369, CEP: 13560-970 369 Sao Carlos, Sao Paulo (Brazil)

2008-02-15

424

Thermal stability and spectral properties of Er 3+-doped gadolinium borosilicate glasses  

NASA Astrophysics Data System (ADS)

A new glass of Gd 2O 3-B 2O 3-SiO 2-Na 2O-Er 2O 3 system is prepared and the formation range of the glass is experimentally obtained. Excellent thermal stability of the glass has been demonstrated using differential thermal analysis. Effects of the B 2O 3 content on the infrared spectral properties such as the 1.5 ?m emission bandwidth and the Judd-Ofelt parameter ?t ( t = 2, 4, 6) of Er 3+ ions in the glass has been observed. The glass exhibits a large integrated emission cross sections for the 1.5 ?m emission band. The Er 3+-doped gadolinium borosilicate glass is a great candidate for broadband erbium doped fiber amplifiers.

Sun, Jiangting; Zhang, Jiahua; Luo, Yongshi; Lu, Shaozhe; Ren, Xinguang; Chen, Baojiu; Wang, Xiaojun

2006-03-01

425

Raman and Photoluminescence Spectroscopy of Er(3+) Doped Heavy Metal Oxide Glasses  

NASA Technical Reports Server (NTRS)

The potential applications of rare-earth ion doped materials include fiber lasers which can be pumped conveniently by infrared semiconductor laser diodes. The host material systems most widely studied are fluoride crystals and glasses because fluorides have low nonradiative relaxation rates due to their lower phonon energies. However, the mechanical strength, chemical durability and temperature stability of the oxide glasses are generally much better than fluoride glasses. The objective of this research was to investigate the optical and spectroscopic properties of Er(3+)-doped lead-germanate and lead-tellurium-germanate glasses. The maximum vibrational energy of lead-tellurium-germanate glasses are in the range of 740-820/cm, intermediate between those of silicate (1150/cm) and fluoride (530/cm) glasses.

Dyer, Keith; Pan, Zheng-Da; Morgan, Steve

1997-01-01

426

Synthesis and in vitro bioactivity of a borate-based bioglass  

Microsoft Academic Search

A bioactive borate glass was synthesized through normal melting-derived route in this letter. The degradation and bioactivity of the glass were studied by the immersion of glass microspheres in a dilute K2HPO4 solution. The cell growth inhibition rate of the borate glass was examined by MTT assay. The conversion product of the borate glass was identified by XRD, SEM. It

Jia Ning; Aihua Yao; Deping Wang; Wenhai Huang; Hailuo Fu; Xin Liu; Xinquan Jiang; Xiuli Zhang

2007-01-01

427

Ho(3+)-doped nanophase glass ceramics for efficiency enhancement in silicon solar cells.  

PubMed

Currently Er(3+)-doped fluorides are being used as upconversion phosphors to enhance the efficiency of Si solar cells, to our knowledge. However, this enhancement is strongly limited owing to the small solar spectral range around 1540 nm that is used. We demonstrate that Ho(3+)-doped oxyfluoride glass ceramics are adequate to enlarge the Si sub-bandgap region around 1170 nm that can be transformed into higher-energy photons, showing an upconversion efficiency 2 orders of magnitude higher than the precursor glass. As these materials are transparent at 1540 nm, they can be used complementarily with Er(3+)-doped phosphors for the same purpose. PMID:19079513

Lahoz, Fernando

2008-12-15

428

Anti-Stokes laser-induced internal cooling of Yb3+-doped glasses  

Microsoft Academic Search

Anti-Stokes cooling between room temperature and 77 K in a fluorochloride glass (CNBZn) and a fluoride glass (BIG) doped with 1 mol % of YbF3 has been demonstrated by using collinear photothermal deflection and conventional laser excitation spectroscopies under high photon irradiances. The cooling efficiency for CNBZn glass which is ~2.0% relative to the absorbed laser power at 1010 nm

J. Fernández; A. Mendioroz; A. J. García; R. Balda; J. L. Adam

2000-01-01

429

Laser-induced internal cooling of Yb 3+-doped fluoride-based glasses  

Microsoft Academic Search

Laser-induced internal cooling between room temperature and 77 K in a new fluorochloride glass (CNBZn) and a fluoride glass (BIG) doped with 1 mol% of YbF3 has been demonstrated by using collinear photothermal deflection and conventional laser excitation spectroscopies under high photon irradiances. The cooling efficiency for CNBZn glass which is ?2.0% relative to the absorbed laser power at 1010

J Fernández; A Mendioroz; A. J Garc??a; R Balda; J. L Adam

2001-01-01

430

Neodymium-doped ion-exchanged waveguide lasers in BK7 glass  

Microsoft Academic Search

The availability of integrated optical sources in glass is expected greatly to enhance optical signal processing in glass substrates. A study of potassium ion-exchanged waveguide lasers in neodymium-doped BK-7 glass substrates is reported. Design parameters for low-threshold waveguide lasers with high slope efficiencies are described, and methods are given for the fabrication of substrates, waveguides and laser cavities. Properties of

Eustace K. Mwarania; Ji Wang; James S. Wilkinson

1993-01-01

431

Preparation and laser induced damage properties of rare earth doped BAS glass  

Microsoft Academic Search

Rare earth doped B2O3-Al2O3-SiO2 glass (RExBAS, x=5, 10, 20; RE=La, Sm) were prepared by solid state reaction method. Optical transmission spectra of such glass were characterized by ultraviolet spectrometers, and 1064 nm laser induced damage performance was investigated through the method of “1-on-1”. The results indicated that there was a strong absorptive peak near 1064 nm in SmxBAS glass, the

Yaru NI; Zhongzi XU; Chunhua LU; Yan ZHANG; Qitu ZHANG

2008-01-01

432

Properties of laser-induced gratings in Eu-doped glasses  

Microsoft Academic Search

The properties of permanent, laser-induced gratings were studied in Eu3+-doped glasses. These gratings are associated with a structural modification of the glass host in the local environment of the Eu3+ ions, and we have investigated the effects produced by altering the Eu3+ concentration and by changing the composition of the glass host. A two-level-system model is developed to explain the

Edward G. Behrens; Frederic M. Durville; Richard C. Powell; Douglas H. Blackburn

1989-01-01

433

Study on luminescent property of Tb(3+)-doped silicate nano-scintillating glass.  

PubMed

By optimizing a Tb(3+)-doped silicate nano-scintillating glass matrix, sensitizer and brightening agent components, the processing conditions such as the melting temperature, holding time, atmosphere, and heat treatment were improved, and the temperature of the heat treatment was changed to generate BaF2 nano-crystal in the glass. The resulting nanocrystals have a better rare earth solubility and a lower phonon energy; therefore the luminescent property of Tb(3+)-doped silicate nano-scintillating glass has been noticeably improved. PMID:20355612

Jingwen, Lv; Xu, Yang; Shengchun, Xiao; Tao, Zheng

2010-03-01

434

Laser induced breakdown spectroscopy diagnosis of rare earth doped optical glasses  

SciTech Connect

In the present work, rare earth (Nd, Eu, Er, Ho) doped oxyfluoroborate glasses were studied using laser induced breakdown spectroscopy (LIBS) technique. It has been observed that rare earth elements other than the doped one also reveal their presence in the spectrum. In addition the spectral lines of elements constituting the glass matrix have also been observed. Different plasma parameters such as plasma temperature and electron density have been estimated. It is concluded that the LIBS is a potential technique to identify simultaneously the light elements (B, O, F) as well as the heavy elements (Fe, Ba, Ca, Eu, Nd, Ho, Er) present in optical glasses.

Dwivedi, Y.; Thakur, S. N.; Rai, S. B.

2010-05-01

435

Properties and structure of Yb 3+ doped zinc aluminum silicate phosphate glasses  

Microsoft Academic Search

This study explores a series of optical, thermal, and structural properties based on 60P2O5–30ZnO–10Al2O3 (60P) glasses that doped with varied rare earth (RE) elements Yb2O3 and P2O5 components replaced by SiO2. It was found that the glasses density decrease with SiO2 concentration added to replace P2O5, whereas they increase with increased concentration of Yb3+-doped. Moreover, the glasses transition temperature, softening

J. Y. Hu; H.-W. Yang; Y. J. Chen; J. S. Lin; C. H. Lai; Y. M. Lee; T. Zhang

2011-01-01

436

Green-white-yellow tunable luminescence from doped transparent glass ceramics containing nanocrystals  

NASA Astrophysics Data System (ADS)

, , and doped transparent ceramics containing nanocrystals were fabricated by a melt-quenching method and subsequent heating. Tetragonal phase spheres with 20 nm size are homogeneously precipitated among a borosilicate glass matrix. The photoluminescence spectrum of single doped transparent ceramics shows white light emission under 382 nm UV excitation. The emission color of co-doped transparent glass ceramics is tuned from green to white through energy transfer from to , and the emission color of co-doped transparent ceramics is tuned from white to yellow through energy transfer from to . CIE chromaticity and color temperature measurements show that the resulting transparent glass ceramics may be a candidate as a warm-white LED material pumped by a UV InGaN chip.

Wang, X. F.; Yan, X. H.; Xuan, Y.; Zheng, J.; He, W. Y.

2013-10-01

437

High humidity resistance of high-power white-light-emitting diode modules employing Ce:YAG doped glass  

Microsoft Academic Search

The reliability study of thermal shock and damp heat tests for high-power white-light-emitting diode modules (WLEDMs) incorporating Ce:YAG doped glass, instead of conventional Ce:YAG doped silicone, as a phosphor layer is presented. The Ce:YAG doped glass as a phosphor layer is used for the glass to possess high transition temperature (Tg) of 750? that can exhibit higher thermal stability and

Chun-Chin Tsai; Jyun-Sian Liou; Wei-Chih Cheng; Cheng-Hsun Chung; Ming-Hung Chen; Jimmy Wang; Wood-Hi Cheng

2011-01-01

438

Preparation of CdS-doped glasses by the sol-gel method  

NASA Astrophysics Data System (ADS)

CdS-doped Si02 glasses have been prepared through the sol-gel process. A methanol solution of cadmium nitrate and thiourea in a molar ratio of 1:2 was added to the Si02 sol prepared from silicon tetraethoxide. The mixed solution was left for gelation at 50 °C and thereby complexes of cadmium nitrate with thiourea were confined in the gel. The gel obtained was then heat-treated at 350 °C in air for the decomposition of the complexes to CdS, the elimination of residual organics, and the densification. The above process produced the transparent Si02 glasses doped with CdS microcrystallites up to Cd/Si = 0.05. The optical absorption edge of the CdS-doped glasses moved to longer wavelengths from that of non-doped Si02 glasses with increasing Cd/Si ratio. The size of CdS microcrystallites in the glasses was further controllable with the additional heat-treatment at around 400°C in a lO H2S/90% Ar stream. For these CdS microcrystallite-doped glasses, the peak of photoluminescence was shifted to shorter wavelengths relative to the absorption edge of CdS crystal, in agreement with the blue shift of the optical absorption edge; these shifts were indicative of the quantum size effects.

Tohge, Noboru; Asuka, Masahiro; Minami, Tsutomu

1990-11-01

439

Thermal Stability and Optical Activity of Erbium Doped Chalcogenide Glasses for Photonics  

NASA Astrophysics Data System (ADS)

The glass transition and crystallization temperatures (T g , T c ), heat capacity, thermal stability and glass uniformity of GeSGa, GeSeGa, Ge(SeTe)Ga chalcogenide glasses doped with Er3+ by the addition of Er2S3 have been investigated by conventional differential scanning calorimetry (DSC) and Temperature-Modulated DSC (TMDSC). While some of the glasses have two crystallization peaks, these glasses were nonetheless optically actively and uniform. Essential optical properties have been evaluated, such as the photoluminescence (PL) intensity and lifetime as a function of the glass composition. We present typical results to emphasize some of the important characteristics of these systems and discuss trends within a glass system; and also highlight differences between glass systems.

Tonchev, D.; Koughia, K.; Kasap, S. O.; Maeda, K.; Sakai, T.; Ikuta, J.; Ivanova, Z. G.

440

Spectroscopy of Yb:Tm doped tellurite glasses for efficient infrared fiber laser  

NASA Astrophysics Data System (ADS)

We performed extensive spectroscopy of tellurite glasses doped with high concentration of Tm ions for laser emission at around 2 micron wavelength. The aim of the work is to develop a glass suitable for single-frequency fiber laser. In fact such a kind of laser require the use of short cavity length and therefore high gain per unit length medium. Tellurite glasses allows high-doping concentration and are therefore an excellent candidate. In these paper we review our recent results. In particular we address the optical and thermo-mechanical properties of several tellurite glasses (75mol%Te02.20mol%ZnO. 5mol%Na2O) with Tm3+ doping up to 111,564 ppm.

Gebavi, H.; Taher, M.; Lousteau, J.; Milanese, D.; Taccheo, S.; Schulzgen, A.; Ferraris, M.; Peyghambarian, N.

2010-02-01