Patent ID: 8604126

Claim:
An optical material obtained by heat-curing an optical material-forming silicone resin composition at a temperature of at least 250° C., said optical material-forming silicone resin composition comprising an inorganic filler which has been surface-treated with a silylating agent or silane coupling agent and a silicon base polymer obtained from dehydration reaction of a silicon base monomer comprising a hydrolyzable silane compound (A), wherein said hydrolyzable silane compound (A) has at least a pair of silicon atoms linked by a linking group which is a straight, branched or cyclic aliphatic hydrocarbon group of 1 to 6 carbon atoms or an aromatic ring-containing hydrocarbon group of 6 to 12 carbon atoms, said at least a pair of silicon atoms having attached thereto at least three substituent groups selected from hydrogen, hydroxyl and hydrolyzable groups, in total, said silicon base monomer contains at least 70 mol % on a silicon basis of the hydrolyzable silane compound (A), a proportion of aromatic structure-containing substituent groups in the substituent groups, inclusive of the linking group, on silicon atoms of the silicon base monomer is up to 30 mol % of the entire silicon-bonded substituent groups.