Results obtained in the qualitative evaluation of glasses from seven IVA-VA-VIA ternary systems as high temperature infrared window materials are given. Four-component glasses formed from two ternary systems were prepared and characterized. The pertinent physical properties of non-oxide chalcogenide glasses are summarized. Several specific glass compositions were fabricated in large pieces so that their optical and related physical properties could be accurately measured. The properties of a glass are determined by their constituent elements. The ratios between the constituent elements, and thus the location of the glass-forming region, are found to depend on the binary compounds which form between the constituent elements.nThe physical and the chemical nature of non-oxide chalcogenide glasses were investigated using infrared spectroscopy, x-ray diffraction, and mass spectrometry as structural tools. It was found the materials were covalently bonded solids and their refractive indexes could be predicted using a molar refraction approach. The source of most unwanted absorption for wave¬lengths below 25 microns was attributed to the presence of trace amounts of metallic oxides. Infrared absorption and x-ray diffraction results indicate the group IVA elements silicon and germanium form zigzag chains with the chalcogens, whi1e the group VA element arsenic tends to form pyramidal-type molecules The chains lead to a stronger, harder glass than the pyramidal arrangements. In Si-As-Te and Ge-As-Te glasses, mass spectrometry results indicate the presence of free or loosely bonded arsenic, arsenic bonded to tellurium, and arsenic bonded to silicon and germanium.
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