Casting technique for organic glass has been developed by means of radiation-induced polymerization of acrylic monomer in a supercooled state at low temperature. It was found that transparent polymer product without optical strain in static strain gauge could be prepared efficiently in a very short time by this method. The micro-strain was also examined by means of Twyman-Michelson type interferometer and the product at low temperature showed very small micro-strain. The reason for these facts can be attributed to the extremely high viscosity, the minimum temperature rising due to polymerization heat and the small volume contract during polymerization in this casting method. The practical monomeric systems consisting of mainly CR-39 and of mainly MMA were applied to this method and excellent materials were obtained as the result. Furthermore, the continuous production method for line focus Fresnel lenses has been developed by radiation polymerization using the soft gel sheet which dose not flow, but is soft and plastic.
