THE EFFECTS OF SN AND BI ADDITIONS ON PROPERTIES AND STRUCTURE IN GE-SE-TE CHALCOGENIDE GLASS

The effects of Sn and Bi additions on the properties and structure in Ge2Se5Te3 glass have been studied by X-ray diffractometry, differentia l thermal analysis (DTA), analysis of weight-loss in solution, infrare d (IR) transmission spectra and far Fourier-transform infrared (far FT IR) spectra for the purpose of expanding the IR transparency region of the Ge-Se-Te system glass and to decrease the fibre's attenuation at 10.6 mu m. The additional Sn atom, which has formed [SnSe4] tetrahedra , another type of network former in the glass network, increased the g lass transition and crystallization temperatures, T-g and T-c, respect ively, anti-crystallisation stability, chemical durability and IR mult iphonon edge. The optimum glass composition in this quaternary system has a quantitative ratio (mol) of Ge/Sn approximate to 2. The most out standing advantages of the Ge-Se-Te-Bi glass system are its excellent chemical durability and broad IR transparency region (the multiphonon absorption edge has been extended to 17.6 mu m, 1.2 mu m longer compar ed with the Ge-Se-Te system glass). Meanwhile, other properties of thi s glass are still somewhat better than the original Ge-Se-Te glass. Th ese two chalcogenide glasses are candidates for drawing fibres for far -infrared transmission, especially for CO2 laser radiation (10.6 mu m) delivery in various environments.