A copolycarbonate includes 0.005-0.1 mole percent of sulfur-containing carbonate units derived from a sulfur-containing bisphenol monomer, 2-95 mole percent of high heat carbonate units derived from a high heat aromatic dihydroxy monomer, and 5-98 mole percent of a low heat carbonate units derived from a low heat aromatic monomer, each based on the sum of the moles of the carbonate units; and optionally, thioether carbonyl endcaps of the formula —C(═O)-L-S—R, wherein L is a C1-12 aliphatic or aromatic linking group and R is a C1-20 alkyl, C6-18 aryl, or C7-24 arylalkylene; wherein the sulfur content of the high heat copolycarbonate in the absence of the thioether endcaps is from 5-20 parts per million by weight.