Abstract
The incorporation of photochromic molecules by physical way (dissolution, dispersion) or chemical way (covalent bond) in organic chains (particularly polymers) or organic-inorganic hybrids leads to the development of a new class of materials, named photochromic materials. These photochromic materials have applications in the unconventional optic area, their properties being shaped with the help of light.
The properties’ shaping doesn’t referred merely to spectacular modifications of detected macroscopic color, but also and to same of series of microscopic properties which are variable in the course of these energetic transitions. In the application field based on photochromia, the most used photochromic materials are the azo derivatives. The interest for this class of compounds is justified on a side through the thermal and chemical stability, the easiness of the azo sequences generation, as well as through versatility of this sequences at action of energetic stimuli.