UV-induced index changes in Undoped Fluoride glass

Undoped fluoride glass slides have been exposed to pulsed 193-nm ultraviolet (UV) irradiation. Their absorption changes have been measured to evaluate UV-induced index changes using Kramers-Kronig relation. A layer-peeling polishing technique was applied to characterize the local UV-induced index change of highly absorbing glass. Index changes up to 1.75/spl times/10/sup -4/ have been evaluated with this method in fluorozirco-aluminate glass. Fluoroaluminate and fluorozirconate glass showed only small index changes of about 2.0/spl times/10/sup -6/ and 2.6/spl times/10/sup -6/ at a wavelength of 1550 nm.