Patent ID: 7358321

Claim:
A copolycarbonate, comprising units of the formula (1) wherein 70 to 99.5 mole percent of the total number of R 1 groups are derived from a dihydroxy compound of formula (2) wherein R 2 and R 3 are each independently a halogen or a C 1-6 alkyl group, R 4 is a phenyl group, and each c is independently 0 to 4; and 0.5 to 30 mole percent of the total number of R 1 groups are derived from a dihydroxy compound of formula (3) HO—R 5 —OH (3) wherein at least 60% of the R 5 groups are aromatic, and the dihydroxy compound of formula (3) is not the same as the dihydroxy compound of formula (2), and wherein the copolycarbonate has a glass transition temperature of 250° C. to 285° C., and a molecular weight of 40,000 to 150,000, measured by gel permeation chromatography using polycarbonate standards.