A NANOSECOND TRANSIENT ABSORPTION STUDY OF PHOTOINDUCED HEAT-GENERATION IN MICROCRYSTALS OF CHI-METAL-FREE PHTHALOCYANINE DISPERSED IN POLYMER-FILMS

Nanosecond transient absorption spectra were recorded following pulsed nanosecond laser excitation at 640 nm of dispersions of chi-metal-fre e phthalocyanine in a film made either of copolymer of styrene and n-b utyl methacrylate (70:30) or of bisphenol A-polycarbonate. The transie nt absorption spectra of the dye in a polymer matrix differ significan tly from those obtained after laser excitation of phthalocyanine molec ules in solution. Referring to the temperature difference spectra of t he ground state absorption spectra and the effect of immersion of the polymer film into a solvent, the transient detected between 650 and 80 0 nm was assigned to a photoinduced thermal phenomenon.