Nanosecond transient absorption study of photoinduced heat generation in microcrystals of X-metal-free phthalocyanine dispersed in polymer films

Nanosecond transient absorption spectra were recorded following pulsed nanosecond laser excitation at 640 nm of dispersions of X-metal-free phthalocyanine in a film made either of copolymer of styrene and n-butyl methacrylate (70:30) or of bisphenol A-polycarbonate. The transient absorption spectra of the dye in a polymer matrix differ significantly from those obtained after laser excitation of phthalocyanine molecules in solution. Referring to the temperature difference spectra of the ground state absorption spectra and the effect of immersion of the polymer film into a solvent, the transient detected between 650 and 800 nm was assigned to a photoinduced thermal phenomenon.