Fast Photochromic Polymers Carrying [2.2]Paracyclophane-Bridged Imidazole Dimer

Abstract

The synthesis and photochromic behavior of the fast photochromic polymers carrying [2.2]paracyclophane-bridged imidazole dimer are demonstrated. A significant feature of this synthetic strategy is that we can modify the photochromic properties such as coloration/decoloration rate, coloring, and photosensitivity via the stepwise synthetic approach of the imidazole dimer system. Notably, the photochromic behavior of the polymers is not affected by the environment around the photochromes and copolymerization with other monomers in both solution and film, which cannot be realized in any other conventional photochromic systems. The comparable photochromic behavior of the homopolymers and copolymers in solution and film indicates that the photochromic unit is independent from the local environment, which allows effective molecular design of the photochromic monomer unit to accomplish desired photochromic properties of the polymer.