John L Kropp; Maurice W Windsor; TRW SYSTEMS GROUP REDONDO BEACH CALIF.
The photochromic behavior of hetero-aromatic molecules was studied. Particular attention has been given to the transient absorption in the polymer host poly(methyl methacrylate). Compounds studied include 1,2;5,6 dibenzacridine, dibenzo(c, g)carbazole, 6 aminochrysene and alpha-naphthoflavone. The latter two compounds show little triplet-triplet absorption, however, the former two compounds do show good absorption. The effect of varying concentration upon T-T absorption was studied and high concentrations (0.01M) seem to show lower intensities of triplet absorption than do some less concentrated samples. The degradation of the samples under exposure to sunlight and an Hg lamp are studied. The degradation due to sunlight is found to be partially reversed overnight. Dibenzo(c, g)carbazole shows far more degradation than does 1,2;5,6 dibenzacridine. Further possible uses of photochromics in military applications are considered. (Author).