Studies On Photochromic Properties Of Fulgide And Its Applications

Fulgide is well-known as a thermally irreversible organic photochromic compound. It is one of the important materials in the field of optical signal processing and optical storage. Focusing on the photochromic properties and applications of fulgide films, I mainly completed the following works.1. The photochromic properties of one kind of pyrrylfulgide/PMMA film and one kind of indoly-benzylfulgimide/PMMA film were studied. The absorption spectra of the E-form and C-form were measured. The photoinduced refractive index change of the films were measured by the method of Michelson interference at several laser wavelengths, which were compared with the theoretical spectra calculated by using Kramers-Kronig relations. The absorption kinetic curve and the two-beam complementary suppression curve of fulgide film were experimentally measured and the parameters such as photochemical reaction constants γ^E→C and γ^C→E were obtained by fitting them with the first-order approximation formulae as well as numerical calculation method, in which the effect of the laser beam profile of intensity distribution was taken into account. The nonlinear two-photon absorption photochromism of the films were studied qualitatively.2. The applications of optical image storage of fulgide films were carried out by using their photochromic properties. The optical storage properties, i.e., sensitive spectral range, sensitivity, spatial resolution, fatigue resistance and thermal stability, were measured. According to these results, the appropriate wavelength and exposure were chosen and the parallel optical data storage was realized, whose storage density was 10⁷bit/cm². Two-photon absorption optical image storage was demonstated by using the nonlinear two-photon absorption photochromic property. Two-wavelength optical image storage was realized on the bicolor photochromic fulgides composite film.3. Photoinduced anisotropy was found in fulgide films and the mechanism was...