Photochromism of Styrene-Derived Polymers having Pendant Phenoxyquinone Moieties

Abstract

The development of efficient photochromic compounds has gained much attention in fundamental and applied research areas. Among numerous photochromic compounds, certain phenoxy naphthacenquinone derivatives are riveting molecules due to their excellent properties such as low fatigue as well as negligible thermal interconversion at room temperature. For example, the "trans"-quinone form of 1-phenoxy-5,12-naphthacenequinone undergoes a photochemical rearrangement to the "ana"-quinone form upon irradition with UV light. One obvious way to make the photochromic compound more suitable for practical application is to incorporate the chromophore into a polymer chain as pendant groups since polymers can be spin-coated on solid substrates to make thin films. It is surprising that not many results have been reported on the synthesis of polymer bound phenoxyquinone derivatives in light of their novel properties. In the literature reported elsewhere, direct radical polymerizations of various acrylate monomers were failed due to the quinone moities which presumably acted as radical scavengers and/or as catalyst poisons. In this study, we report the successful direct synthesis of styrene-derived polymer having pendent phenoxyquinones derivatives for photochromism. Polymers having quinone moieties were prepared by AIBN-initiated radical polymerization. Synthesis of the monomers was straightforward and the polymer was obtained in a reasonably high yield.