Composition Dependence of Elastic Modulus in Binary Tellurite Glasses

抄録

Elastic moduli of some binary tellurite glasses were measured by using a cube-resonance method. The glass systems employed were MgO-TeO₂, ZnO-TeO₂, MoO₃-TeO₂, and WO₃-TeO₂. Young′s moduli of most glasses can be predicted using the compositional parameters based on the Makishima-Mackenzie theory. In the systems containing divalent cations(Mg²⁺ or Zn²⁺), Young′s modulus of MgO-TeO₂ glass was larger than that of ZnO-TeO₂ glass because of the higher dissociation energy of MgO. In the case of the glasses containing hexavalent cations(Mo⁶⁺ or W⁶⁺), although the dissociation energy and the packing density factor of MoO₃ and WO₃ are comparable with each other, Young′s modulus of MoO₃-TeO₂ glass was smaller than that of WO₃-TeO₂ glass. This is because the smaller electro-negativity of Mo⁶⁺ ion results in smaller oxygen coordination for Mo atom. The larger molar volume of MoO₃-TeO₂ glass also supports this loose structure.