Structure investigation of TeO2–BaO glass employing ultrasonic study

Tellurite glasses of the system (100 − x)TeO2–xBaO for different compositions of BaO (x = 9, 12, 15, 18, 20 and 22 wt.%) have been prepared by rapid quenching method. A decrease in ultrasonic velocities and density, which is followed by an increase in attenuation with a progressive increase in BaO content has been observed at room temperature and also over a wide range of temperatures. The above results reveal the softening of the glass network due to the progressive transformation of the rigid framework characteristics of TeO2 resulting in the formation of distorted TeO3 + 1 units followed by the creation of regular TeO2 (4 → 3 + 1 → 3) sites and the formation of ionic character bond (NBO).