Photoreaction constants of fulgide films at different wavelengths

Two kinds of synthesized photochromic fulgide — pyrrylfulgide (F1) and 3-indoly-benzylfulgimide (F2) — are prepared as thin films doped in a polymethyl methacrylate (PMMA) matrix. Under irradiation by 405nm laser, the films convert from the colorless E-form (bleached state) into the C-form (colored state). When the C-forms are irradiated by 488nm, 514nm, 633nm or 650nm laser, the films returns to the E-forms. The photochromic kinetics of them under the irradiation of different wavelength lights (405nm, 488nm, 514nm, 633nm and 650nm) and the two-beam complementary suppression curve of F2 film under the irradiation of 633nm and 405nm lights are experimentally measured, which are simulated by using the first order kinetics and numerical calculation methods and the best simulating values of the photoreaction constants are obtained and compared. Under the irradiation of 633nm light, the photoreaction constants of the bleaching progress in F1 and F2 films (equation) are 1.4×10⁻³ cm²/mJ and 2.89×10⁻³ cm²/mJ respectively. Under the irradiation of 488nm, 514nm and 650nm lights, the relative values of photoreaction constant equation are same with the theoretical values getting from the absorption spectra and equation. The two-beam complementary suppression curves proved that equation and equation getting from the single beam irradiation curves are correct. And it is found that non-uniformity distribution of exciting light intensity has great affection to the deviation of the transmission curve from the first order dynamic curve.