Method for injection molding of optical discs

A method for controlling the heat transfer in a process for molding an optical disc having a plurality of laser readable depressions of a predetermined quality wherein the process steps comprise injecting molten thermoplastic material at a temperature from 200 degrees C. to about 400 degrees C. into a mold having opposing surfaces for replicating respective opposite sides of the disc and imparting optically readable depressions of a predetermined quality to at least one side of said disc, said thermoplastic material having a glass transition temperature in the range of 110 to about 175 degrees Centigrade, said mold being of the type having a thermally conductive mold body and opposing thermally conductive members, each member having a respective opposing surface for forming opposite sides of said optical disc, said mold including a pair of insulating members, each insulating member positioned between said conductive mold body and a respective opposing thermally conductive member, maintaining said thermally conductive mold body at a temperature less then about 90 degrees Centigrade wherein said insulting members are selected so that the molten thermoplastic resin is evenly and rapidly cooled during injection molding from opposing sides to a temperature within about 5 degrees Centigrade of the glass transition temperature of said resin.