The invention is directed to chalcogenide glasses suitable for use in
plastics forming processes. The glasses have the general formula YZ,
where Y is Ge, As, Sb or a mixture of two or more of the sane; Z is Se,
Te, or a mixture of Se+Te; and Y and Z are present in amounts (in
atomic/element percent) in the range of Y=15-70% and Z=30-85%. The
chalcogenide glasses of the invention have a 10,000 poise temperature of
400.degree. C. and are resistant to crystallization when processed at
high shear rates at their 10,000 poise temperature. The glasses can be
used to make, among other items, molded telecommunication elements,
lenses and infrared sensing devices.