Formation of surface defects on polymer lenses depending on moisture absorption

Lenses for eye glasses of thermosetting material CR39 and optical lenses of polycarbonate have been investigated with respect to their moisture absorption behavior. The moisture content of polymer lenses has been determined by analyzing transmission spectra in the near infrared (NIR). The surface topography was characterized by Atomic Force Microscopy (AFM). In spite of the fact that CR39 takes up essentially more water, the formation of surface defects is not remarkable compared with lenses of polycarbonate.