Patent ID: 8064140

Claim:
An optical grade article comprising a thermoplastic composition comprising a poly(aliphatic ester)-polycarbonate copolymer comprising the following monomeric units: 10 to 25 wt % of a soft block ester unit derived from a C 20-44 aliphatic dicarboxylic acid or derivative thereof, 34 to 77 wt % of a carbonate unit derived from 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, 0 to 76 wt % of a carbonate unit derived from a dihydroxyaromatic compound excluding 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, and wherein the sum of the weight percentages of soft block ester units, 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine units, and dihydroxyaromatic compound units is 100 weight percent of the monomeric units of the poly(aliphatic ester)-polycarbonate, and wherein the refractive index of the thermoplastic composition is greater than or equal to 1.590, and the glass transition temperature of the copolymer is from 120 to 155° C.