PHOTOCHROMIC EYE-PROTECTIVE DEVICE BASED ON TRIPLET ABSORPTION.
Annual research rept. no. 7, 1 Sep 65-31 Aug 66,
TRW SYSTEMS REDONDO BEACH CALIF CHEMICAL SCIENCES DEPT
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A prototype 6 x 8-inch photochromic windshield segment was developed and delivered to the Air Force. The device is designed to protect pilots against flash blindness caused by exposure to nuclear explosions. The reversible photochromic darkening is based upon absorption of visible light by metastable triplet states of aromatic molecules. The active compounds are incorporated into solid sheets of transparent plastic. Three sheets of plastic are arranged in an N-type configuration and the triplet states are produced by UV excitation from two flash lamps. Black glass filters prevent visible light from the flash lamps from dazzling the observer. With a 1900 joule input to the flash lamps, the triplet-state windshield segment attains within one millisecond an optical density, weighted for eye-response, that varies from 1.4 along a line midway between the flash lamps to 2.7 close to each flash lamp. The open-state transmittance is 65 and the device re-opens to one-half this transmittance in approximately 2 seconds. Author
- Radiation and Nuclear Chemistry
- Protective Equipment