Structural Thermo and Phototransformations of Oxaindane Spiropyrans Adsorbed on Silver Films.

Using giant Raman scattering spectroscopy methods, we have studied the structure and also the thermo and phototransformations of dimethylphthalanspirobenzopyran (PhSBP) adsorbed on the surface of silver films. It is shown that on adsorption of PhSBP from ethanol solutions, on the surface of the silver films there are predominantly open forms of molecules which do not exhibit photochromic properties. It is established that cooling of the specimen to 77 K initiates thermoreversible reconstruction of the adsorption layer with formation of the aggregates of the PhSBP molecules. These reversible structural changes in frozen specimens are enhanced on exposure to the light of a visible range. [ABSTRACT FROM AUTHOR]