Structure and elastic properties of TeO2–BaF2 glasses

Binary tellurite (100−x)TeO2–xBaF2 glasses for different compositions of BaF2 (x=8x=8, 10, 12, 15, 18 and 20 wt%) have been prepared by rapid quenching method. The velocities and attenuation during the propagation of the ultrasonic waves in all glasses were measured using a transducer operated at a fundamental frequency of 5 MHz at room temperature. A progressive increase in BaF2 content leads to a decrease in ultrasonic velocities and density, which is followed by an increase in attenuation. The existence of depolymerisation of Te co-ordination leads to the transformation of TeO4 trigonal bipyramid units through TeO3+1 polyhedron to TeO3 trigonal pyramid units. This is responsible for the observed decrease in the measured and determined parameters with the addition of the modifier content.