| 摘要 |
PROBLEM TO BE SOLVED: To improve heat resistance and adhesion with a coating material by treating a fiber core comprising a specified hydrogen-added polymer with a compound having a different refractive index from that of the hydrogen-added polymer so as to continuously change the refractive index from the peripheral part of the core to the inner part. SOLUTION: A fiber core comprising a hydrogen-added polymer is treated with a compd. having different refractive index from that of the hydrogen-added polymer so as to continuously change the refractive index from the peripheral part of the fiber core to the inner part of the core. The hydrogen-added polymer is prepared by ring-opening polymn. of monomers comprising at least one kind of norbornene deriv. expressed by formula or copolymerizable monomers which copolymerize with the monomers. In formula, A and B are hydrogen atoms or hydrocarbon groups having 1 to 10 carbon atoms, X and Y are hydrogen atoms or univalent org. groups and at least one of X and Y is a polar group except for hydrogen and hydrocarbon groups, and (m) is 0 or 1. |
