Femtosecond spectrochronography of the reverse photochromic transition in derivatives of spiro compounds

The photochromic properties of the merocyanines of a spiropyran, a spironap hthooxazine and a crown-containing spironaphthooxazine as well as complexes of these compounds with metal ions were studied. Various mechanisms for th e reverse photochromic transition and the possibility of dissociation of th e ionic complexes under the action of femtosecond-scale light pulses were d iscussed. A kinetic model describing the experimental results was developed under the assumption that the process of isomerization plays the main role in the cycle of photochemical transformations.