RESEARCH ON TRIPLET STATES AND PHOTOCHROMISM.
Semi-annual Research rept. no. 5, 25 Jan-30 Sep 64,
TRW SYSTEMS REDONDO BEACH CALIF QUANTUM PHYSICS LAB
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The report describes research studies on the photochromic properties of the triplet states of aromatic compounds for application to the problem of flash blindness protection. Effort was concentrated on the measurement of optical densities attained as a function of flash energy, since it is this parameter which is of greatest improtance for evaluating materials for flash protection. An OD of 2 was obtained for a chrysene sample with a flash energy of 380J. Several pairs of compounds appear promising in providing broad coverage on the basis of curves constructed by adding together their T-T absorption spectra. Fatigue studies on chrysene in PMM plastic show that the samples withstand four weeks exposure to sunlight without noticeable fatigue but that the T-T absorption has decreased by about a factor of 2 or 3 after eight weeks exposure. The core effect, previously attributed to quenching by the diffusion of atmospheric oxygen into the plastic has been shown to be reversible when samples are pumped in vacuum while being either heated or irradiated with a sun lamp. A clear epoxy plastic has been developed in which the solubility of chrysene is 110 sq M. This may lead to thinner photochromic specimens. Fluorescence yields of more than a dozen aromatics were measured. Author
- Radiation and Nuclear Chemistry
- Protective Equipment