Electrical and optical properties of some sodium borate glasses

The dc-electrical conductivity of sodium borate glasses containing different metal oxides namely MgO, CaO, SrO, BaO, CdO and Al2O3 with different percents was measured in the temperature range 35–510°C. The activation energies of the electrical conduction and the glass transition temperature were calculated. DTA was carried out for the samples containing 5% MgO and 1% Al2O3 to identify phase transitions. All the results were discussed and correlated according to the molecular structure of the prepared glasses. Also, the absorption spectra were measured in the 190–900 nm range and interpreted in the terms of structural concepts. A resolution of the observed absorption spectra showed that four bands were induced with maxima at about 210, 270, 420 and 680 nm. Small deviations of these induced bands characteristic of the glass content were observed and explained in terms of the physical properties of the contained metal oxides.