GLASS-FORMATION, PROPERTIES AND STRUCTURE OF GLASSES IN THE TEO2-ZNO SYSTEM

Glass formation occurs in the zinc tellurite system in the region of the eutectic (21 mol% ZnO) on the TeO2-rich side of the phase diagram. Glasses are characterized by a high refractive index which increases with TeO2 content. The glasses are transmitting from about 400 nm to about 6 mum with O-H absorption bands at 3.3 and 4.4 mum. Short range order of the glasses was deduced with neutron diffraction, infrared and Raman spectroscopy by comparison with the spectra of the synthesized crystalline alpha-TeO2, Zn2Te3O8 and ZnTeO3. Glasses consist of disordered TeO4, TeO3+1 and TeO3 building units. The number of the TeO3+1 units is limited by ZnO addition. There is a relatively strong structural correlation between the glasses and the crystalline compound Zn2Te3O8 in accord with the phase diagram.