Process for preparing highly-cured transparent resin molded products

A process for the production of a highly-cured transparent resin formed product, which comprises (1) incorporating a ring-opening and cross-linking catalyst in the initial monomer composition comprising (a) from about 1% to 100% by weight of a glycidyl ester selected from the group consisting of glycidyl methacrylate, glycidyl acrylate and a mixture thereof and (b) from 0% to about 99% by weight of one or more other vinyl monomers at temperatures within the range of from about -50.degree. C to room temperature, followed by vinyl-polymerizing the initial monomer composition thus prepared in a mold into a vinyl polymer at 90% or more conversion by irradiating said composition with an ionizing radiation at temperatures within the range of from about -50.degree. C to room temperature so as not to activate said ring-opening and cross-linking catalyst, (2) remolding the thus obtained vinyl polymer having thermoplasticity into the desired shape and (3) heating the molded product at a temperature of from about 50.degree. C to about 200.degree. C for several minutes to tens of hours to highly-cure the molded polymer product by the introduction of cross-linking.