Interaction of ruby laser radiation with a transparent solution of photochromic spiropyran

A numerical analysis was made of a system of equations describing the interaction between a laser pulse and a photochromic medium. The results obtained were compared with the experimental data obtained in an investigation of the two-photon excitation of photochromic transitions in a solution of 8'-allyl-6'-nitro-1,3,3-trimethyl-spiro-(2'H-1-benzopyran-2', 2-indoline) in toluene. An earlier hypothesis of a considerable influence of one-photon bleaching of the colored form of this compound on the nature of the two-photon coloration of a solution of spiropyran was confirmed. It was established that spiropyran photochromic systems could be used to measure temporal and spatial characteristics of laser pulses.