Patent ID: 8787723

Claim:
A resin composition for forming an optical waveguide, comprising (A) a polyhydroxy polyether having an ethylenically unsaturated group on a side chain and an aromatic ring on a main chain, (B) a polymerizable compound having an ethylenically unsaturated group, and (C) a radical polymerization initiator, wherein the component (A) has structural units represented by the following general formulae (3) and (2), wherein the polyhydroxy polyether has structural units represented by the general formula (3) in a content of 3 to 70% by mol, and has structural units represented by the general formula (2) in a content of 30 to 97% by mol: wherein R 36 represents a hydrogen atom or a methyl group; X 1 represents a divalent group selected from wherein R 2 to R 18 each independently represent a hydrogen atom, a fluorine atom or an organic group having from 1 to 20 carbon atoms; Z 1 represents a single bond or a divalent group selected from an oxygen atom, a sulfur atom, —CH 2 —, —C(CH 3 ) 2 —, —CF 2 —, —C(CF 3 ) 2 —, —SO 2 —, wherein a represents an integer of from 2 to 10; Y 1 represents a single bond or a divalent organic group having from 1 to 20 carbon atoms; and Y 4 represents a divalent organic group having from 1 to 18 carbon atoms, and wherein X 2 represents a divalent group selected from wherein R 19 to R 35 each independently represent a hydrogen atom, a fluorine atom or an organic group having from 1 to 20 carbon atoms; Z 2 represents a single bond, an oxygen atom, a sulfur atom or a divalent group selected from —CH 2 —, —C(CH 3 ) 2 —, —CF 2 —, —C(CF 3 ) 2 —, —SO 2 —, wherein b represents an integer of from 2 to 10; and Y 3 represents a single bond or a divalent organic group having from 1 to 20 carbon atoms.