Raman spectra of binary tellurite glasses containing tri- or tetra-valent cations

Abstract

Glass formation and structure are investigated in binary tellurite systems containing YO 3/2, InO 3/2, LaO 3/2, ZrO 2, SnO 2, HfO 2, and ThO 2 as second components. No glasses are obtained in two systems, ZrO 2-TeO 2 and SnO 2-TeO 2, because of the precipitation of ZrTe 3O 8 and SnTe 3O 8 crystals. Raman spectra and glass properties, such as transition temperature, thermal expansion and density, were measured. Glasses having low LaO 3/2 content have a continuous network structure composed of corner-sharing TeO 4 trigonal bipyramids and TeO 3+1 polyhedra having one non-bridging oxygen atom. Further increase of LaO 3/2 content accelerates a conversion of TeO 4 trigonal bipyramids and TeO 3+1 polyhedra into TeO 3 trigonal pyramids having two or three non-bridging oxygen atoms. In the YO 3/2-TeO 2 and ThO 2-TeO 2 systems, the change of glass structure follows the same process as in LaO 3/2-TeO 2 glasses. In 23InO 3/2 · 77TeO 2 glass, few structural fragments composed of TeO 3 trigonal pyramids are formed. There is a possibility that 5HfO 2 · 95TeO 2 glass contains a small fraction of structural fragments present in HfTe 3O 8 crystal.