M. Fernández-Rodríguez, V.J. Rico, A.R. González-Elipe, A. Álvarez-Herrero
Physica Status Solidi C, 5 (2008) 1164–1167
doi: 10.1002/pssc.200777790

This paper presents the behaviour of a standard optical coating to be used in aerospace applications when exposed to ultraviolet (UV) irradiation. Ellipsometric measurements are carried out in order to monitor the effects produced on the optical properties of the TiO₂ film when it is exposed to a 500 W Xenon lamp during the time intervals of 1 hour, 22 hours and 42 hours. The ellipsometric measurements show that main changes occur in the real part of the refractive index after the first hour of exposure to UV irradiation. To assess a possible relation between the hydrophilicity that the UV irradiation typically induces on the TiO₂ thin film, and the variation of the optical properties of the film, the water contact angle on the TiO₂optical coating was also measured after irradiation under similar conditions