Thermal and optical properties of GeS2-based chalcogenide glasses

Glasses compositions which can be expressed by (100−x)GeS2–xGa2S3 (x=0, 10, 20, 30 mol%), 70GeS2–(30−x)Ga2S3–xCdS (x=0, 10, 15, 20 mol%), and (100−x)GeS2–x[0.5Ga2S3–0.5CdS] (x=0, 10, 20, 30, 40 mol%), were obtained by the melt-quenching technique. Differential scanning calorimetry (DSC) and visible-IR transmission were used to characterize the thermal and optical properties of these glasses, together with refractive index and density measurements. These homogeneous glasses have relatively high glass transition temperatures (338–436 °C), good thermal stabilities, broad transparencies (0.45–11.5 μm), large refractive indices (2.01–2.25), and large densities (2.68–3.18 g cm−3). The long-wavelength cutoff edge is found near 12 μm due to the multiphonon Ge–S and Ga–S vibrations. The compositional dependences of selected properties were also discussed by making reference to the structural variation.