Patent ID: 7031591

Claim:
An optical waveguide formed from an optical waveguide-forming material, said optical waveguide-forming material comprising a photocurable organopolysiloxane composition comprising an alkali-soluble organopolysiloxane and a photoacid generator, said organopolysiloxane possessing hydroxyl groups resulting from ring-opening of some or all of epoxides, and being obtained by (co)hydrolytic condensation of at least one silane compound having the formula (1): R 1 Si(OR 2 ) 3 (1) wherein R 1 is a monovalent organo group of 2 to 30 carbon atoms having hydrolyzable epoxide, and R 2 is hydrogen or a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms, and having an average molecular weight of 500 to 50,000 as determined by GPC using polystyrene standards, wherein said (co)hydrolytic condensation comprises carrying out (co)hydrolysis in the presence of an acid catalyst, thereby forming a (co)hydrolyzate, and then subjecting the (co)hydrolyzate to polycondensation, while alcohol formed and any solvent present is distilled off by heating, thereby yielding a (co)hydrolytic condensate having silanol groups.