Optical Analysis of Metal Oxide Borosilicate (xCaO(1-x-z) SiO2 zB2O3) glasses with varying concentrations of boric oxide (B2O3)

Abstract

Glass sample compositions of xCaO(1-x-z)-SiO2 zB2O3 with constant nominal CaO of x=33.33 mol% and varying concentrations of B2O3 as z=50,60 and 66.67 mol% are prepared by conventional melt quench technique. Fourier transform infrared (FTIR) spectra of xCaO(1-x-z)-SiO2 zB2O3 glass system has been measured in the spectral range 400–4000 cm−1 low-frequency region 1700cm-1 to 400cm-1 and high-frequency region 4000cm-1 to 1700cm-1) at room temperature to understand the characteristic frequencies of the chemical bonds, bonding mechanisms and structure of electron shell of atoms, for the purpose to determine the molecular structure of the composition. It is found that the melting temperature of the glasses decreases with the increase of B2O3 concentration and the melting temperature in the range of 950oC-1100oC for the samples which consist of 50, 60, and 66.67 mol% of B2O3. In the low-frequency region (1700cm-1 to 400cm-1) the spectra of high B2O3 containing glass showed an increased number of distinct peaks and several broad Gaussian in the thigh-frequency region (1700cm-1 to 400cm-1). All the spectra are based on line corrected and deconvoluted to the appropriate number of Gaussians. Fourier transform infrared (FTIR) deconvoluted spectra were analyzed to determine the exact position and relative amounts of the IR bands responsible for the different silicate borates units. The distinct peaks and peak position of the deconvoluted Gaussians are assigned to Si-O-Si, B-O-B, Si-O-Ca, Si-O etc. bonds based on the previous scientific investigations. The presence of B2O3 in the materials suggests that B3+ occupies the network position and for the linkage Si-O-B in the glasses. The amorphous nature, the surface topography and composition of the prepared glasses was checked by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques respectively on optical inspection, did not show any evidence of phase separation, and all glasses are homogeneous.