Crystallization study of infrared transmitting glass ceramics based on GeS2–Sb2S3–CsClGeS2–Sb2S3–CsCl

The crystallization of the GeS2–Sb2S3–CsClGeS2–Sb2S3–CsCl glasses has been studied in order to obtain transparent glass ceramics. X-ray diffraction, scanning electronic microscope and nuclear magnetic resonance have been used for identifying the crystallized phases and to estimate crystal content. It has been demonstrated that the partially substituted CsCl is the main crystalline phase at the beginning of ceramization. Crystals with size smaller than 50 nm are homogenously distributed inside the glass matrix. Despite of the huge difference of refractive index between the crystals and the glass, glass ceramics with more than 50% of crystals are still transparent, especially in the infrared region.