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1.
Glass samples of composition xAl2O3-20PbO-(80−x)B2O3 and xWO3-xAl2O3-20PbO-(80−2x)B2O3 with x varying from 0% to 10% mole fraction are prepared by melt quench technique. The optical band gap decreases (from 3.21 to 2.37 eV) more for WO3-Al2O3-PbO-B2O3 glasses with an addition of WO3 content. The FTIR spectral studies have pointed out the conversion of structural units of BO3 to BO4 and WO4 to WO6 in these glasses. The increase in density from 4.51 to 5.80 g cm−3 for WO3-Al2O3-PbO-B2O3 glasses is observed with an increase in WO3 content. This is observed that the atomic structure changes more with the incorporation of WO3. This is due to the formation of WO6, WO4 and BO4 units.  相似文献   

2.
Glass samples of compositions xZnO-xCeO2-(30−x)PbO-(70−x)B2O3 with x varying from 2% to 10% mole fraction are prepared by the melt quench technique. The structural and optical analysis of glasses is carried out by XRD, FTIR, density and UV-visible spectroscopic measurement techniques. The FTIR spectral analysis indicates that with the addition of ZnO contents in glass network, structural units of BO3 are transformed into BO4. It has been observed in our previous work that band gap decreases from 2.89 to 2.30 eV for CeO2-PbO-B2O3 glasses with cerium content varying from 0% to 10% [Gurinder Pal Singh, Davinder Paul Singh, Physica B 406(3) (2011) 640-644]. With the incorporation of zinc in CeO2-PbO-B2O3 glasses, the optical band gap energy decreases further from 2.38 to 2.03 eV. This causes more compaction of the borate network, which results in an increase of density (3.39-4.02 g/cm3). Transmittance shows that ZnO in glass samples acts as a reducing agent thathelps to convert Ce4+→Ce3+ ions.  相似文献   

3.
Structural analysis of x[(100−y)Ag2yMnO]·(100−x)[2B2O3·As2O3] glasses, with x=10 mol% and 0≤y≤10 mol%, was performed by means of FT-IR and FT-Raman spectroscopies. The purpose of this work is to investigate the structural changes that appear in the xAg2O·(100−x)·[2B2O3·As2O3] glasses with the addition and increase in manganese ions content. FT-IR measurements revealed the presence of pyro-, ortho-, di-, tri-, tetra- and penta-borate groups and structural units characteristic to As2O3 in the structure of the studied glasses. FT-IR spectroscopy measurements also show that BO3 units are the main structural units of the glass system. The presence of structural units characteristic to Ag2O were not directly evidenced by FT-IR spectroscopy. In addtition, the FT-Raman analysis evidenced the presence of boroxol rings in the structure of the studied glasses.  相似文献   

4.
xV2O5xCeO2–(30−x)PbO–(70−x) B2O3 glasses are synthesized by using the melt quench technique. The number of studies such as XRD, density, molar volume, optical band gap, refractive index and FTIR spectroscopy are employed to characterize the glasses. The band gap decreases from 2.20 to 1.78 eV and density increases from 3.49 to 4.25 g/cm3. FTIR spectroscopy reveals that incorporation of V2O5 in glass network helps to convert the structural units of [BO3] into [BO4]. At higher concentration of vanadium, VO vibration of [VO5] structural units and V–O–V vibration are present. The bond ionicity of glasses increases with incorporation of V2O5 contents.  相似文献   

5.
Pure and WO3 doped CeO2-PbO-B2O3 glasses are prepared by the melt-quench technique. The structural and optical analyses of glasses are carried out by XRD, FTIR, density and UV-vis spectroscopic measurement techniques. FTIR analysis indicates the transformation of structural units of BO3 into BO4 with W-O-W vibration and the presence of WO4 and WO6 units observed with increase in WO3 contents. Decrease in band gap for CeO2-PbO-B2O3 glasses from 2.89 to 2.30 eV and for WO3 doped glasses from 2.89 to 1.95 eV has been observed and discussed. This decrease in band gap with WO3 doping approaches to semiconductor behavior. It shows that the presence of WO3 in the glass samples causes more compaction of the borate network due to the formation of BO4 groups and the presence of WO4 and WO6 groups, which result in a decrease in the optical band gap energy and increase in the density.  相似文献   

6.
The glasses of the composition (40−x) PbO-15Bi2O3-45As2O3-xCoO, with 0≤x≤0.6 mol% in the steps of 0.1 were synthesized. The dielectric properties viz., dielectric constant, loss and ac conductivity over moderately larger ranges of frequency and temperature were investigated. The results were analyzed with the aid of the data on optical absorption and IR spectra. The analysis indicated that there is an increase in the insulating strength of the glasses with increase in the concentration of CoO up to 0.4 mol%.  相似文献   

7.
20LiF-(30−x)Sb2O3-50B2O3:xNiO glasses with the value of x (ranging from 0 to 1.0 mol% in steps of 0.2) were prepared. A number of studies, viz. differential scanning calorimetry, optical absorption, magnetic susceptibility and thermoluminescence, on these glasses were carried out as a function of nickel ion concentration. An anomaly has been observed in all the properties of these glasses when NiO concentration is about 0.6 mol%. The results of these studies were analysed in the light of different environments of nickel ions in the glass network.  相似文献   

8.
In a three-components fluorophosphate glass system, the introduction of H3BO3 brings some valuable influence to the spectroscopic and thermal properties of the glasses. With H3BO3 increases from 2 to 20 mol%, Ω6, Sed4I13/2, FWHM, Tg and fluorescence lifetime change from 3.21×10−20 cm2, 1.77×10−20 cm2, 45 nm, 480 °C and 8.8 ms to 4.66×10−20 cm2, 2.11×10−20 cm2, 50 nm, 541 °C and 7.4 ms, respectively. σabs, σemi, FWHM×τf×σemi has a maximum when H3BO3 is 11 mol%. Tg and TxTg increases with H3BO3 introduction. Results showed that in fluorophosphate glasses, proper amount of B2O3 can be used as a modifier to suppress upconversion and improve spectroscopic properties, broadband property and crystallization stability of the glasses while keeps the fluorescence lifetime relatively high.  相似文献   

9.
Lithium borate (LiB) glasses in the system (100−x)B2O3-xLi2O with x=20, 30, 40, 50, 60 and 70 mol% were prepared. The glasses were doped with different concentrations of the order of 10−1, 10−2, 10−3, 10−4 and 10−5 of MgO and their thermoluminescent (TL) response was investigated. The irradiations were performed using γ rays from a 60Co source in the dose range from 0.1 to 25 kGy. The material displayed good sensitivity for γ-rays and intensity of TL signals is dependent on γ-ray dose and Li2O content. For each dose level and investigated temperature range (50-350 °C), exactly single isolated glow peak appears in the temperature range of 165-205 °C depending on both Li2O concentrations and time of exposure. The shape of the glow peak has altered significantly with increase in the gamma ray dose or Li2O concentrations. The glass composition with x=50 mol% doped with 10−3 mol% of MgO presented the best TL response. The results of the present study indicated that the recorded single and isolated high temperature peak is a good candidate for TL dosimetric investigations. This indicates that 50 B2O3-50Li2O-doped with 10−3 mol% of MgO is possibly used as materials for radiation dosimetry in the dose range of 0.1-20 kGy.  相似文献   

10.
Two-dimensional crystal curved lines consisting of the nonlinear optical SmxBi1−xBO3 phase are fabricated at the surface of 8Sm2O3·37Bi2O3·55B2O3 glass by continuous wave Nd:YAG laser (wavelength: 1064 nm) irradiation (samarium atom heat processing) with a power of ∼0.9 W and a laser scanning speed of 5 μm/s. The curved lines with bending angles of 0-90° or with sine-shapes are written by just changing the laser scanning direction. The polarized micro-Raman scattering spectra for the line after bending are the same as those for the line before bending, indicating that the crystal plane of SmxBi1−xBO3 crystals to the crystal growth direction might be maintained even after the change in the laser scanning direction. It is found from laser scanning microscope observations that the crystal lines at the surface are swelled out smoothly, giving a height of about 10 μm.  相似文献   

11.
Longitudinal and shear ultrasonic wave velocities have been measured in different compositions of the glass system 20Li2O-(80−x)B2O3-xWO3 (0?x?12.5 mol%), at room temperature and at 4 MHz frequency. Elastic moduli, Debye temperature and Poisson's ratio have been obtained as a function of WO3 content. Based on FTIR spectroscopy and theoretical bond compression model, quantitative analysis has been carried out in order to obtain more information about the structure of these glasses. The longitudinal ultrasonic wave velocity measurements showed a bend at about 2.5 mol% WO3 content while shear ultrasonic wave velocity decreased monotonously with an increase of WO3 content. Elastic moduli values decreased as WO3 content increased from 0 to 2.5 mol%. Further increase of WO3 beyond 2.5 mol% increased the elastic moduli values. It is suggested that these behaviours are mainly due to the presence of WO3 in the network structure of these glasses as a network modifier when WO3 content is between 0 and 2.5 mol%, and acts as a network former above 2.5 mol%.  相似文献   

12.
Glasses with composition xBi2O3·(30−x)M2O·70B2O3 (M=Li, Na) containing 2 mol% V2O5 have been prepared over the range 0≤x≤15 (x is in mol%). The electron paramagnetic resonance spectra of VO2+ of these glasses have been recorded in the X-band (≈9.3 GHz) at room temperature (RT≈300 K). Spin Hamiltonian parameters, g, g, A, A, dipolar hyperfine coupling parameter, P, and Fermi contact interaction parameter, K, have been calculated. The molecular orbital coefficients, α2 and γ2, have been calculated by recording the optical transmission spectra. In xBi2O3·(30−x)Li2O·70B2O3 glasses there is decrease in the tetragonality of the V4+O6 complex for x up to 6 mol% whereas for x≥6 mol%, tetragonality increases. In xBi2O3·(30−x)Na2O·70B2O3 glasses there is increase in the tetragonality of the V4+O6 complex with increasing x. The 3dxy orbit expands with increase in Bi2O3:M2O ratio. Values of the theoretical optical basicity, Λth, have also been reported. The DC conductivity increases with increase in temperature. The order of conductivity is 10−5 ohm−1 m−1 at low temperature and 10−3 ohm−1 m−1 at high temperature. The DC conductivity decreases and the activation energy increases with increase in Bi2O3:M2O ratio.  相似文献   

13.
Glasses with composition xWO3·(30−x)M2O·70B2O3 (M=Li, Na; 0≤x≤15) doped with 2 mol% V2O5 have been prepared using the melt-quench technique. The electron paramagnetic resonance spectra have been recorded in X-band (ν≈9.14 GHz) at room temperature (RT). 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) only due to V4+ ions, which exist as VO2+ ions in octahedral coordination with a tetragonal compression in the present glass system. The tetragonality increases with WO3:M2O ratio and also there is an expansion of 3dxy orbit of unpaired electron in the vanadium ion. The study of IR transmission spectra over a range 400-4000 cm−1 depicts the presence of WO6 group. The DC conductivity (σ) has been measured in the temperature range 423-623 K and is found to be predominantly ionic.  相似文献   

14.
A series of Er3+/Yb3+-co-doped 60Bi2O3-(40−x) B2O3 -xGa2O3 (BBGA x=0, 4, 8, 12, 16 mol%) glasses have been prepared. The absorption spectra, emission spectra, fluorescence lifetime of Er3+:4I13/2 level and thermal stability were measured and investigated. Three Judd-Ofelt intensity parameters Ωt (t=2,4,6) (Ω2=(4.67-5.93)×10−20 cm2, Ω4=(1.50-1.81)×10−20 cm2, Ω6=(0.92-1.17)×10−20 cm2) of Er3+ ions were calculated by Judd-Ofelt theory. It is found that the Ω6 first increases with the increase of Ga2O3 content from 0 to 8 mol% and then decreases, which is mainly affected by the number of non-bridging oxygen ions of the glass network. The high peak of stimulated emission cross-section () of Er3+: 4I13/24I15/2 transition were obtained according to McCumber theory and broad full width at half maximum (FWHM=69-76 nm) of the 4I13/24I15/2 transition of Er3+ ions were measured. The results indicate that these new BBGA glasses can be used as a candidate host material for potential broadband optical amplifiers.  相似文献   

15.
The needle shape single crystals Co3−x MnxO2BO3 with ludwigite structure have been prepared. According to the X-ray diffraction data the preferable character of distinct crystallographic positions occupation by Mn ions is established. Magnetization field and temperature dependencies are measured. Paramagnetic Curie temperature value Θ=−100 K points out the predominance of antiferromagnetic interactions. Spin-glass magnetic ordering takes the onset at TN=41 K. The crystallographic and magnetic properties of Co3O2BO3:Mn are compared with the same for the isostructural analogs Co3O2BO3 and CoO2BO3:Fe.  相似文献   

16.
We report, for the first time the study of mixed alkali effect (MAE) in boroarsenate glasses. Density, DSC, DC electrical conductivity and IR studies have been carried out for xK2O-(40−x)Na2O-50B2O3-10As2O3 glasses. The DC electrical conductivity was measured in the temperature range 100 °C to below the glass transition temperature. The strength of the MAE in Tg, DC electrical conductivity and activation energy has been determined. It is observed that the strength of MAE in DC electrical conductivity is less pronounced with increase in temperature. The results are explained by the structural model recently proposed by Swenson and coworkers, supporting molecular dynamic results. The IR studies show that the glass system contains BO3 and BO4 units in the disordered manner.  相似文献   

17.
xCeO2–30Bi2O3–(70−x) B2O3 glasses are synthesized by using the melt quench technique. A number of studies such as XRD, density, molar volume, optical band gap, refractive index and FTIR spectroscopy are employed to characterize the glasses. The band gap decreases from 2.15 to 1.61 eV, refractive index increases from 2.67 to 2.93 and density increases from 4.151 to 4.633 g/cm3. The decrease in band gap with CeO2 doping approaches the semiconductor behavior. FTIR spectroscopy reveals that incorporation of CeO2 into glass network helps to convert the structural units of [BO3] into [BO4] and results in Bi–O bond vibration of [BiO6].  相似文献   

18.
We have developed a new series of zinc lead borate (ZLB) glasses by varying ZnO content, to enhance UV transmission, in the chemical composition of xZnO-15PbO-(85−x)B2O3, where x=0, 5, 10, 15, 20, 25, 30, 35, 40 and 45 mol% ZnO. From the measurement of UV absorption spectra both the direct and indirect band gaps have been evaluated. Also different physical properties of a reference glass of 45ZnO-15PbO-40B2O3 have been studied. From the measurement of refractive indices at six different wavelengths, Cauchy's constants (A=1.578743209; and ) have been computed and a satisfactory correlation has been achieved between the theoretical and the experimental results. Absorption spectra of Cu2+(45−x)ZnO-15PbO-40B2O3 (where x=0.1, 0.2, 0.5 and 1.0 mol%) have shown two absorption bands at 428 nm (2B1g2Eg) and 777 nm (2B1g2B2g). Emission spectra of (1.0 mol%) Cu2+:ZLB have revealed two emission transitions at 400 and 493 nm with excitations at 288 and 316 nm.  相似文献   

19.
Lead bismuth arsenate glasses mixed with different concentrations of WO3 (ranging from 0 to 6.0 mol%) were synthesized. Differential thermal analysis (DTA), optical absorption, ESR and IR spectral studies have been carried out. The results of DTA have indicated that there is a gradual decrease in the resistance of the glass against devitrification with increase in the concentration of WO3 upto 4.0 mol%.The optical absorption spectra of these glasses exhibited a relatively broad band peaking at about 880 nm identified due to dxydx2y2 transition of W5+ ions; this band is observed to be more intense in the spectrum of glass containing 4.0 mol% of WO3. Further, two prominent kinks attributed to 3P01S0, 1D2 transitions of Bi3+ ions have also been located in the absorption spectra. The ESR spectra of these glasses recorded at room temperature exhibited an asymmetric signal at g∼1.71 and gll∼1.61. The intensity of the signal is observed to be maximal for the spectrum of the glass W4. The quantitative analysis of optical absorption and ESR spectral studies have indicated that there is a maximum reduction of tungsten ions from W6+ state to W5+ state in the glass containing 4.0 mol% of WO3. The IR spectral studies have indicated that there is a increasing degree of disorder in the glass network with increase in the concentration of WO3 upto 4.0 mol%.  相似文献   

20.
The elastic properties and Debye temperatures of xB2O3–70TeO2–(30–x)WO3, (0 ≤ x ≤ 30 mol%) glasses have been investigated using sound velocity measurements at 4 MHz. Ultrasonic and thermal parameters, combined with the results of IR spectroscopic analyses, were employed to explore the effect of B2O3 on the structure of tungsten–tellurite glasses. According to IR analysis, there is competition between WO6 and TeO4 units to form BO4 units, and the vibrations of the tellurite structural units are shifted towards lower wavenumbers on the formation of non-bridging oxygens. It is assumed that B2O3 acts as a modifier by decreasing the glass-transition temperature T g and increasing both the thermal stability and glass formation range of the tellurite glasses. The change in density and molar volume with B2O3 content reveals that the borate units are less dense than the tellurite structural units. The observed compositional dependence of elastic moduli is interpreted in terms of the effect of B2O3 on the coordination number of the tellurite units. A good correlation was observed between experimentally determined elastic moduli and those computed with the Makishima–Mackenzie model.  相似文献   

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