Tellurium and iodine were added to a base chalcogenide glass composition (Ge33Asl2Se5S) to compare their effects
on physical and optical properties. Iodine decreased the glass transition temperature and increased thermal expansion to a
greater extent than tellurium. However, density was lowered by the presence of iodine and increased by tellurium.
Examination of the multiphonon absorption edge in the 300-900 cm1 range revealed that iodine and tellurium occupy
different structural sites which accounts for their varied effect on physical properties. There appears to be no advantage of
iodine versus tellurium additions with regard to optical fiber applications based on the results obtained.
Robin J. MacKinnon,
George H. Sigel,
"Optical and physical effects of iodine in chalcohalide glasses", Proc. SPIE 1228, Infrared Fiber Optics II, (1 May 1990); doi: 10.1117/12.18632; https://doi.org/10.1117/12.18632