On the thermal and photochemical stabilities of photochromic spirooxazine dyes encapsulated in Ormocer matrices derived by sol-gel processing

Abstract

Spiroindolinonaphthoxazine (abbreviated as SO), a most promising class of photochromic dyes due to their better photochromic response to UV irradiation (e.g. sunlight), higher fading rate of the coloured form and higher photofatigue resistance, is incorporated into Ormocer matrices synthesized by the sol-gel route aiming to achieve some application prospects. As for all technical applications the stability of the martials as a function of time and /or under certain harsh circumstances must be considered and improved if necessary. In the present work the thermal and photochemical stabilities of our photochromic SO-Ormocer gels and coatings are investigated by room temperature (RT) holding, heat treatment and UV irradiation experiments and compared with the SO-PMMA coatings. It is shown by our results that both the thermal and photochemical stabilities of our SO-Ormocer coatings are similar to those of the SO-PMMA coatings. Considering that both the photochromic response and the fading rate of our SO-Ormocer coatings are much better than those of the SO-PMMA coatings, it is reasonable to conclude that the overall performance of our SO-Ormocer coatings is acceptable for certain application purposes.