SULFUR-CONTAINING CYCLIC COMPOUND AND OPTICAL MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide an optical material capable of improving heat resistance which had trouble in a conventional dopant and having slight change of distribution of refractive index. SOLUTION: A sulfur-containing cyclic compound having a specific structure is used as a dopant. Reliability of transmission characteristic as optical fiber is improved by improving heat stability of refractive index distribution and the optical material is usable for the long period even in a field in which heat resistance is required, e.g. engine room of automobile in which a conventional refractive index distribution type polymer optical fiber could not be used.