Photobleaching of organic laser dyes in solid matrices.

A technique is described for measuring the rate of photobleaching of anisotropic dye molecules in solid polymer matrices. Three dyes of different classes in two matrices (PMMA and epoxy resin) show bleaching rates that differ by a factor of 20. The bleaching rate is linearly proportional to the intensity of incident radiation, indicating a one-photon process; bleaching is probably due to a chemical reaction of the dye in its first excited singlet or lowest triplet state.