Photochromic polymers based on the photoinduced opening and thermal closing of [l,3]Oxazine rings

Abstract

Two macromolecular constructs incorporating a single polymer backbone with multiple photochrome side chains are deváoped. Both systems are prepared from preformed photochrome |1,3]oxazines after the ring-opening polymerization of their norbornene appendages. In solution, UV illumination of these polymers opens the [1,3]oxazine rings in their side chains in less than 6 ns and with a quantum yield of 0.09 in both instances. The photogenerated species incorporate a 4-nitrophenolate chromophore, and hence, their formation is accompanied by the appearance of an intense band in the visible region of the absorption spectrum. The photoproducts revert spontaneously to the original state with first-order kinetics in microseconds. Furthermore, both photochrome polymers tolerate hundreds of switching cycles with no sign of degradation, even in the presence of molecular oxygen. Thus, this design logic and choice of functional building blocks can translate into the realization of innovative photo responsive materials with excellent photochrome performance. © 2009 WILEY-VCH Verlag GmbH &. Co. KCaA.