Thermal, optical and structural properties of glasses within the TeO2-TiO2-ZnO system

A glass-forming domain was evidenced and studied within the TeO2-TiO2-ZnO system. Density, glass transition temperature (T-g) and onset crystallization temperature (T-o) were measured and interpreted as a function of the zinc oxide mole fraction for relevant glasses. It was concluded that the zinc oxide favors the thermal stability of glasses. On the other hand, the impact of TiO2 addition is even more pronounced on the enhancement of the thermal stability. The optical transmission was recorded for series of glasses in the UV-Visible-NIR range. Refractive index and optical band gap were extracted from these measurements and studied as a function of the ZnO content. Linear refractive indices and optical band gap were found to decrease and increase respectively, with increasing ZnO content. The third-order non-linear susceptibility Re (X-3), measured for two series of glasses (TiO2 content was fixed either to 5 or 10 mol%), was found to progressively decrease when the ZnO concentration increases. The impact of ZnO modifier on the glass structure was discussed based on Raman spectroscopy data. We evidenced that TiO2 does not change drastically the glass network, whereas ZnO leads in a first step to the breaking of the Te-O-Te bridges, inducing network depolymerization. A further addition in ZnO leads to the formation of new Te-O-Zn and Zn-O-Zn linkages. (C) 2014 Elsevier B.V. All rights reserved.