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 same; Z is S,
Se, Te, or a mixture of two or more of the same; 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.