Glass formation, physico-chemical properties, and structure of glasses based on Ga2S3–GeS2–Sb2S3 system

We prepared sulfide glasses based on a Ga2S3–GeS2–Sb2S3 system and investigated the compositional dependences of their physico-chemical properties and structure. Additivities were observed for density and refractive index; i.e., these properties were presented by the summation of the contribution from each component. With the increase of Sb2S3 content, the density, refractive index, and thermal expansion coefficient increased while the glass transition and softening temperatures decreased, and the short-wavelength absorption edge shifted to the longer wavelength side. These variations are expected from the incorporation of a heavy element (Sb) into the glasses. On the other hand, the replacement of GeS2 by Ga2S3 increased the density and refractive index, and shifted the short-wavelength absorption edge to the longer wavelength side. These variations were explained by the increase of the number densities of the cations with the replacement and the formation of metal–metal bonds. The latter was confirmed from the Raman spectra. We also investigated the effects of Ag2S incorporation on the optical properties. The incorporation of Ag2S increased the density and refractive index whereas the position of the short-wavelength absorption edge varied little. These results show the possibility of fabricating an optical waveguide by Ag incorporation into the glasses.