Casting of organic glass by radiation‐induced polymerization of glass‐forming monomers at low temperature. I. Optical strain of thermal stream type

摘要

AbstractIt was found previously that cast articles of transparent polymer without optical strain could be obtained efficiently in a very short time by radiation‐induced polymerization of glass‐forming monomers at low temperature. Two types of optical strain were observed in casting of these monomers: thermal stream type and remaining (inner) stress type strain. The mechanism of thermal stream‐type strain formation was investigated by following the heat and temperature change during cast polymerization in this report. It was found that the temperature difference between the upper and lower part of the sample was large and the temperature was much higher in the upper part than in the lower part under conditions of strain formation. Increase of heat removal from the sample surface decreased the temperature difference in the vertical direction and reduced the strain formation. It could be deduced that stream‐type strain formed as a result of thermal stream and it was retarded in radiation casting of glass‐forming monomers owing to high viscosity and low te