NEAR-INFRARED SPECTROSCOPY FOR MONITORING WATER PERMEABILITY OF OPTICAL COATINGS ON PLASTICS

Near-infrared spectroscopy has been applied to determine the water con tent of plastic lenses. An analytical method is presented for monitori ng the water permeability of thin layers on plastic optics by utilizin g the reversible moisture absorption of organic polymers. As an exampl e, scratch-resistant and antireflective layers on poly[diethylenglycol -bis(allylcarbonate)] lenses are investigated. The measurements demons trate the relatively high water barrier of coatings deposited by plasm a-ion-assisted deposition compared with classical physical vapor depos ition coatings and polysiloxane dip coatings. (C) 1997 Optical Society of America