FLUORESCENCE MEMORY FILM CAPABLE OF REPEATING WRITING AND ERASING, AND PROCESSES FOR WRITING AND RE-PRODUCING NON-DESTRUCTIVE READOUT

摘要

The fluorescence memory film capable of repeating non-destructive readout according to the present invention is prepared by coating on a substrate a melt composition comprising a matrix polymer and a mixture of a fluorophore and a photochromic compound. The fluorophore has preferably a maximum absorption wavelength at about 410 to 430 nm for non-destructive readout capability, and a maximum emission wavelength at about 450 to 700 nm, preferably around 590 nm, the Stokes' shift being about 20 to 290 nm, preferably about 175 nm. The matrix polymer does not emit fluorescence when a visible light with a wavelength of 410-430 nm is irradiated.