MoO3TeO2 glasses were investigated by Raman spectroscopy and differential thermal analysis, and transition temperature, thermal expansion and density were measured. Mo O bonds are present in the entire glass composition. The glasses contain TeO4 trigonal bipyramids, TeO3+1 polyhedra and MoO6 octahedra as basic structural units. Glasses having low MoO3 content contain MoO6 octahedra having two Mo O bonds. As MoO3 content increases, the fraction of Mo O bonds to Mo6+ decreases. When MoO3 content reaches 30–40 mol%, the structure of glasses shows close resemblance to that of MoTe2O7 crystal. On the basis of local structural difference around second-component atoms between MoO3-TeO2 and WO3-TeO2 glasses, differences in the properties of both glasses are discussed.
