ELASTIC PROPERTIES OF BINARY AO(3)-P2O5 AND TERNARY NA2O-AO(3)-P2O5 (A-MO OR W) GLASSES

The elastic properties of several compositions of binary AO(3)-P2O5 an d ternary Na2O-AO(3)-P2O5 (A = Mo or W) glasses have been studied usin g ultrasonic measurements. The trends in the variations in the moduli as a function of composition have been examined. The moduli of the bin ary glasses exhibit opposite trends. In the ternary glasses the variat ions in the moduli are consistent with the nature of the structural un its formed at various compositions. The variations in the Debye and gl ass transition temperatures and the average dimensionality of the glas ses are also examined on the basis of a structural model of the glasse s proposed earlier. The longitudinal modulus, shear modulus and Poisso n ratio are found to vary linearly as a function of the covalent bond energy density and also as a function of the product of total cohesive energy density and average dimensionality.