The preparation and properties of an antimony sulphide glass

A glass has been prepared in the Sb₂S₃PbS system at compositions very close to 80 mol % Sb₂S₃: 20 mol % PbS. It has been studied by powder x-ray diffraction, optical and high resolution transmission microscopy and infra-red spectroscopy, and its decomposition characterised by differential scanning calorimetry. Hardness values are also reported. This glass displays a wide range of transparency from 4.5 to 16.5 μm and may be of interest for a number of infrared applications. Structural studies indicate that it is formed of SbS and PbS polyhedra similar to those found in the crystalline PbSbS sulphides, and recrystallisation of the glass, observed by electron microscopy shows that the rearrangement of the polyhedra in transforming from the glass state to the crystalline state is feasible. The formation of the glass and its limited composition range are discussed in terms of the strain involved in linking the PbS and SbS polyhedra together and this leads to a number of suggestions as to how the existence region over which the glass forms could be expanded.