Thermal stability and far infrared transmitting property of GeTe4-AsTe3-AgI glasses and glass-ceramics

The present GeTe4-AsTe3-AgI glasses extend the optical window to up to 25 μm and its glass-forming region has been explored for practical applications. Their structure, glass-forming ability, thermal stability, infrared transmitting properties were investigated. The results reveal that the GeTe4-AsTe3-AgI glasses exhibit a large glass-forming region situated around the GeTe4-rich domain. Raman analysis confirms the formed [GeTe3I] and [AsTe2I] units are mainly responsible for the improvement in glass-forming ability. The optimum 40GeTe4-30AsTe3-30AgI glasses exhibit a large optical window extending from 2 to 25 μm while being stable enough toward crystallization to permit the preparation of fibers and molded lenses. Under proper annealing at 150 °C, 40GeTe4-30AsTe3-30AgI glass-ceramics, with high mechanical and thermal properties while still keeping the IR transmittance unchanged, were obtained for the first time.