Elastic properties of tellurite glasses

Elastic properties of binary and ternary tellurite glass systems of the composition (in mol%) (100-x) TeO2 - x Nb2O5, and (100-x) TeO2 - 0.5x (Nb2O5 + Li2O) were calculated from the measured densities as well as from longitudinal and shear ultrasonic velocities at room temperature. Ultrasonic velocity measurements were taken at 4 MHz ultrasonic frequency using the pulse echo technique. Elastic moduli, and Debye temperature calculated from experimental data and calculated theoretically using the bond compression model were used to obtain quantitative details about the structure of these glasses. The effect of adding either Nb2O5 alone or Nb2O5 and Li2 on the elastic moduli was investigated in terms of the number of network bonds of the glass systems. The average atomic ring size of the network was also calculated and it was found that it depends on the concentration of the modifiers. The obtained results show that these glasses become more stable and compact when modified with Nb2O5 or with Nb2O5 and Li2O, which increases the elastic moduli in the two systems