Patent ID: 8663508

Claim:
A photochromic curable composition comprising (I) 100 parts by mass of (meth)acrylic polymerizable monomers and (II) 0.01 to 20 parts by mass of a photochromic compound, wherein 100 parts by mass of the (meth)acrylic polymerizable monomers consist of (Ia) 70 to 100 parts by mass of a polyfunctional polymerizable monomer having two to four (meth)acrylic groups in one molecule and (Ib) 0 to 30 parts by mass of a monofunctional polymerizable monomer having one (meth)acrylic group in one molecule; and methacrylic groups and acrylic groups in the (meth)acrylic polymerizable monomers are existent to ensure that the number of moles of the methacrylic group is 3 to 7 times the number of moles of the acrylic group, and the polyfunctional polymerizable monomer (Ia) consists of 60 to 80 mass % of a bifunctional polymerizable monomer having two (meth)acrylic groups, 20 to 40 mass % of a trifunctional polymerizable monomer having three (meth)acrylic groups, and 0 to 20 mass % of a tetrafunctional polymerizable monomer having four (meth)acrylic groups, wherein the total of the bifunctional polymerizable monomer, the trifunctional polymerizable monomer and the tetrafunctional polymerizable monomer is 100 mass %.