Kinetics of photocoloration and photobleaching of (E)‎-dicyclopropylmethylene-(2,5-dimethyl-3-furylethylidene)‎ succinic anhydride doped in a blend PMMA-PS film at different annealing temperatures

Abstract EN

Irradiation of the pale-yellowed color (E)-dicyclopropylmethylene-(2,5-dimethyl-3-furylethylidene)succinic anhydride (fulgide 1-E) doped in a blend of PMMA/PS with UV light (366nm) forms an intense red colored cyclized product, 7,7a-dihydro-7,7-dicyclopropyl-2,4,7a-trimethylbenzo[b]furan-5,6-dicarboxylic anhydride (1-C), which in turn, converted again to the pale- yellow color (fulgide 1- E) when irradiated by white light.

The kinetics of the photocoloration and photobleaching processes were investigated spectrophotometrically.

It was found that both coloration and bleaching reaction rates of fulgide 1 doped in PMMA/PS and its cyclized form, respectively- increase with increasing the annealing temperature, and the rate constant of both processes is slower than those observed for the doped films in either PMMA or PS.

In general, It was observed that the photochromic properties of the annealed films of fulgide 1 improved upon annealing.