Preparation and characterizations of glasses in the TeO₂-Ga₂O₃-M₂O (M=Li, Na, K) systems

Glasses in the TeO2-Ga2O3-M2O (M=Li, Na, or K) systems were synthesized by a melt-quenching technique. The glass forming areas were delimited for each system. Systematic analyses were performed on two series of samples-the first one with a constant TeO2/Ga2O3 ratio of 85/15, that is, [(TeO2)(0.)(85)(Ga2O3)(0.)(15)](100-x)[M2O](x) with 0 <= x <= 25 (with a step of 5 mol%), the second one with a constant alkaline oxide concentration of 10 mol%, that is, [TeO2](90-y)[Ga2O3](y)[M2O](10 )with 5 <= y <= 15 (with step of 2.5 mol%). The values of the glass transition temperature, density, and optical transmission parameters (the positions of short- and long-wavelength absorption edge and the maximum transmittance value) were determined. The changes in these parameters were studied for varying glass compositions. In addition, the values of refractive index were measured at various wavelengths across the whole transparency region reaching from the visible up to the mid-infrared range.