Thermal history of a low alkali borosilicate glass probed by infrared and Raman spectroscopy (original) (raw)
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Structure of alkali borosilicate glasses and melts according to Raman spectroscopy data
Glass Physics and Chemistry
Using the technique of high temperature Raman scattering spectroscopy, we studied the structure of glasses and melts of the systems Na 2 O-B 2 O 3-SiO 2 , K 2 O-B 2 O 3-SiO 2 , and Cs 2 O-B 2 O 3-SiO 2 with the relations X M 2 O / = 1 (M = Na, K, Cs) and / = 3 and 4/3. Based on the analysis of the regis tered spectra, we have shown that, at a high content of SiO 2 , the disordered network of glasses is composed of the Q 4 , Q 3 , [BO 4/2 ]tetrahedrons and BO 3/2 triangles. When the content of SiO 2 reduces, asymmetric borate triangles BØ 2/2 Oare formed in the structure in addition. A substantial part of borate tetrahedrons are included into the content of mixed borosilicate rings composed of two silicon-oxygen and two boron-oxy gen tetrahedrons. The amount of borate structural units joined into purely borate superstructural groups increases with a decrease of the silicon oxide content, depends on the alkali kation type, and grows in the direction from Cs to Na. An increase in the temperature causes a decrease of various types of rings and growth of the concentration of asymmetric triangles. Both in glasses and melts, the fraction of the BO 2/2 Otriangles depends on the alkali cation type and increases in the succession Cs → K → Na. The results obtained present the basis to suggest that there is some differentiation in the mechanisms of structural reconstruction of the glasses under study by their heating depending on the modifying oxide.
Borate glass structure by Raman and infrared spectroscopies
Journal of Molecular Structure, 1991
employed to probe the continuous evolution of borate glass structures as a function of the nature and concentration of alkali oxide modifier. At relatively low alkali contents, the glasses contain covalent networks consisting of interconnected units bearing BO, tetrahedra. Further addition of alkali oxide causes the progressive depolymerization of the network as a result of the formation of non-bridging oxygen atoms. Eventually, complete network disruption into small and highly charged borate units results in "ionic" glasses. The nature of the alkali cation determines the structure of these glasses by affecting several hightemperature isomerization or disproportionation equilibria. *Dedicated to the memory of Professor George Wilkinson. 0022-2860/91/$03,50 0 1991-Elsevier Science Publishers B.V.
A series of glasses were prepared by rapid melt quench method in the glass system (65 − x) [(Ba 0.6 Sr 0.4 )TiO 3 ]-30[2SiO 2 -B 2 O 3 ]-5[K 2 O]-x[La 2 O 3 ] (x = 0, 1, 2, 5 and 10). X-ray diffraction of glass samples were carried to check its amorphousity. Density of glass samples were measured using Archimedes principle. The refractive index of these glass samples lies between 2.39 to 2.80. Optical properties of these glass samples were studied using Infrared (IR) and Raman spectroscopic techniques. IR measurements were done over a continous spectral range 450 -4000 cm -1 to study their stucture networking systematically while Raman spectra were recorded over a continous spectral range 200 -2000 cm -1 . IR spectra of all glass samples showed number of absorption peaks. These absorption peaks occurs due to asymetric vibrational streching of borate by relaxation of the bond B-O of trigonal BO 3 . The Raman spectra of all glass samples exhibited different spectral bands and intensity of these bands changes drastically. The network structure of these glass samples is mainly based on BO 3 and BO 4 units placed in different structural groups.
Open Journal of Inorganic Non-metallic Materials, 2012
A series of glasses were prepared by rapid melt quench method in the glass system (65 − x)[(Ba 0.6 Sr 0.4)TiO 3 ]-30[2SiO 2-B 2 O 3 ]-5[K 2 O]-x[La 2 O 3 ] (x = 0, 1, 2, 5 and 10). X-ray diffraction of glass samples were carried to check its amorphousity. Density of glass samples were measured using Archimedes principle. The refractive index of these glass samples lies between 2.39 to 2.80. Optical properties of these glass samples were studied using Infrared (IR) and Raman spectroscopic techniques. IR measurements were done over a continous spectral range 450-4000 cm-1 to study their stucture networking systematically while Raman spectra were recorded over a continous spectral range 200-2000 cm-1. IR spectra of all glass samples showed number of absorption peaks. These absorption peaks occurs due to asymetric vibrational streching of borate by relaxation of the bond B-O of trigonal BO 3. The Raman spectra of all glass samples exhibited different spectral bands and intensity of these bands changes drastically. The network structure of these glass samples is mainly based on BO 3 and BO 4 units placed in different structural groups.
Thermal poling induced structural changes in sodium borosilicate glasses
… and Chemistry of …, 2009
Abstract: Inorganic glassy materials can exhibit large second order nonlinear optical (NLO) coefficients, χ (2), after thermal poling. Sodium borosilicate glasses with various SiO 2 contents and constant Na 2 O: B 2 O 3 ratio of 0· 2, which characterises the boric oxide ...
Structural characterization of high-zirconia borosilicate glasses using Raman spectroscopy
Journal of Non-Crystalline Solids, 2000
Polarized Raman spectra were obtained for a collection of borosilicate glasses that have been developed as candidate compositions for the immobilization of wastes generated from the reprocessing of Zircaloy-clad spent nuclear fuel. Raman spectra were obtained for borosilicate glasses with zirconia compositions as high as 21 wt%, as well as for crystalline ZrO 2 (baddeleyite) and crystalline ZrSiO 4 (zircon). As zirconia content in the glass is increased, two trends in the spectra indicate that the partially polymerized silicate tetrahedral network becomes more depolymerized: one, the polarized mid frequency envelope near 450 cm À1 , assigned to Si±O±Si symmetrical bend modes, decreases in area; and two, the higher frequency band assigned to Si±O stretch in Q 2 units (silicate chains) increases in area, while band areas decrease for modes assigned to Si±O stretch in more polymerized Q 3 and Q 4 units (silicate sheets and cages). These trends take place whether the glass composition is relatively simple or considerably more complex. As zirconia concentrations in the glass increase beyond 15 wt%, a series of sharp lines are observed in the spectra from baddeleyite crystals, and to a minor extent Zn±Cr spinel phases, superimposed on broad features from the glass matrix. A low intensity, broad band near 1400 cm À1 in the glass spectra is probably due to B±O stretch modes within BO 3 units. Ó
Thermal and mechanical characterization of borosilicate glass
Physics Procedia, 2009
The aim of this work is to characterize thermally (dilatometric analysis) and mechanically a Pyrex type borosilicate glass. The mechanical tests (Vickers indentations, mechanical strength and fracture toughness) were made on the glass in an annealed state and after a chemical strengthening treatment by ionic exchange. The indentations imprints morphologies and details were observed by optical and scanning electron microscopy. The dilatometric analysis shows that the thermal expansion variation with temperature is essentially non linear, increasing rapidly up to 200°C and slowing down beyond. The optimal glass chemical strengthening was obtained for a bath duration of 15 hours. This corresponds to a relatively moderate increase of the mechanical strength (~70%). The fracture toughness measured by indentation was appreciably improved by the chemical treatment. It seems also to increase with the applied indentation load.