Influence of WO3 on some physical properties of MO-Sb2O3-B2O3 (M = Ca, Pb and Zn) glass system

Three series of glasses, of the composition 20 MO (M = Ca, Pb, Zn)-40 Sb2O3-(40 - x)B2O3:xWO3, with six values of x ranging from 0 to 1 mol% were prepared. The samples were characterized by X-ray diffraction, scanning electron microscopy, EDS and differential scanning calorimetric techniques. The DSC studies have indicated the glass forming ability decreases with increase in the concentration of WO3 for all the three series. The comparison of DSC data among the three series has indicated the glass forming ability is higher for ZnO mixed glasses. The IR spectral studies have pointed out the existence of conventional BO3, BO4, SbO3 and WO4 structural units in these glasses. These studies have further indicated the decreasing concentration of symmetrical structural vibrational groups with increase in the concentration of WO3. The results of various studies viz., dielectric properties over a range of frequency and temperature, optical absorption, and ESR spectra at room temperature of MO-Sb2O3-B2O3:WO3 glasses have also been reported. The variations observed in all these properties due to different modifiers as a function of the concentration of WO3 have been analyzed in the light of different oxidation states and environment of tungsten ions in these glasses.