Polycarbonate and optical disc substrate

A polycarbonate resin made up of carbonate bonds having the structure ##STR5## and carbonate bond-constituting units which are structural units between said carbonate bonds, wherein from 25 to 100% of said carbonate bond-constituting units contain at least one pendant aromatic group and have the formula ##STR6## wherein each of X and Y is a hydrogen atom, an aliphatic hydrocarbon group having from 1 to 6 carbon atoms, or an aryl or aralkyl group having from 6 to 12 carbon atoms, provided that at least one of X and Y is an aryl or aralkyl group having from 6 to 12 carbon atoms, and each of Z and W is a hydrogen atom or an aliphatic hydrocarbon group having from 1 to 6 carbon atoms, wherein said polycarbonate resin has an average molecular weight of from 10,400 to 14,000, based on the intrinsic viscosity of said polycarbonate resin at 20.degree. C. in methylene chloride at a concentration of 6.0 g/liter, and wherein the melt flow index of said polycarbonate resin is from 0.86 to 3.2 as measured at 230.degree. C. under a load of 5 kg in accordance with International Standards Organization Reference ISO R-1133.