Accession Number : AD0675323

Title :   TRIPLET TO TRIPLET ABSORPTION IN ORGANIC MOLECULES FOR USE IN PHOTOCHROMIC DEVICES.

Descriptive Note : Final rept. 31 May 67-15 Aug 68,

Corporate Author : TRW SYSTEMS REDONDO BEACH CALIF QUANTUM PHYSICS LAB

Personal Author(s) : Kropp,John L. ; Windsor,Maurice W.

Report Date : AUG 1968

Pagination or Media Count : 72

Abstract : The photochromic properties of several substituted aromatics and heterocyclics have been investigated. The absorption spectra, phosphorescence lifetime T-T absorption spectra and the product of triplet extinction coefficient and triplet formation efficiency, were evaluated for representative compounds. Using these data the photochromic properties of heterocyclics are compared to their hydrocarbon analogs. The values of the maximum triplet formation efficiency are lower for heterocyclics than for aromatics. However, broader T-T absorption and more efficient absorption for pumping light suggest that, on balance, heterocyclics are comparable to aromatic hydrocarbons in their effectiveness as photochromic materials. The variation of solvent induces large changes in the photochromic properties of heterocyclics thus providing a useful additional parameter for adjusting their properties. These differences also promise to shed light on the mechanism of radiationless transitions in these compounds. Recommendations for further studies to improve the photochromic properties of heterocyclics are made. (Author)

Descriptors :   (*POLYCYCLIC COMPOUNDS, PHOTOCHROMISM), (*PHOTOCHROMISM, *MOLECULAR ENERGY LEVELS), AROMATIC COMPOUNDS, HETEROCYCLIC COMPOUNDS, ABSORPTION SPECTRA, PHOSPHORESCENCE, RELAXATION TIME, EXCITATION, OPTICAL PUMPING, ELECTRON TRANSITIONS

Subject Categories : Radiation and Nuclear Chemistry
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE