Crystallization behavior of 80GeS2 ⋅ 20Ga2S3 chalcogenide glass

Glass-ceramics were fabricated from the 80GeS2⋅20Ga2S3 chalcogenide glass using an appropriate heat-treatment at a fairly low temperature (Tg+30°C) for different durations. Compared with the base glass, they present much-improved thermal shock resistance and fracture toughness, and meanwhile remain an excellent mid-IR transmission in 2–10-μm spectral region. XRD results indicate that the enhanced mechanical properties are mainly due to the appearance of Ga2S3 crystals, and only a very small amount of GeS2 was precipitated on the surface. Bulk and powder samples heat-treated at 458°C for different durations were used to study the evolution of the two crystallization peaks using DSC measurement. It is found that the precipitation of Ga2S3 phase is responsible for the exotherm of first crystallization peak and that of GeS2 phase for the second one. The crystallization mechanism was also examined using the nonisothermal method, and the considerably low activation energy (Ec) and high crystallization rate constant (K) for the first crystallization peak illustrate a much easier precipitation of Ga2S3 phase than that of GeS2 phase, which is in good accordance with the ceramization process.