Oxyfluoride glasses containing LiNbO3

The MoO3-BaF2-NaF-ZnF2-NbO2.5-LiNbO3 and NbO2F-BaF2-LiF-LiNbO3 oxyfluoride glass systems were investigated. Glasses were prepared by fusion at 850 deg rees C for 30 min in a platinum crucible and cast in a brass mould at 200 d egrees C. For each system, the effect of the LiNbO3 content (to 15 mol%) on the physical properties of the samples, such as glass transition (T-g) and crystallisation (T-x) temperatures, densities and refractive indices were measured. Density (about 4 g cm(-3)), and refractive index (n > 1.7) were m easured as a function of dopant concentration and glass processing. Optical transmission measurements in the IR range were also carried out and sample s were transparent up to 5 mu m. Thermal analysis by differential scanning calorimetry was used to determine the characteristic temperatures of prepar ed glasses and to define the stability factor (Delta T = T-x - T-g). The gl ass transition temperature of these glasses is about 250 degrees C, with De lta T around 80 degrees C. (C) 1999 Elsevier Science B.V. All rights reserv ed.