Accession Number : AD0672849

Title :   FLUORESCENCE AND PHOSPHORESCENCE OF AROMATIC HYDROCARBONS IN POLY(METHYLMETHACRYLATE) AS A FUNCTION OF TEMPERATURE,

Corporate Author : TRW SYSTEMS REDONDO BEACH CALIF CHEMICAL SCIENCES DEPT

Personal Author(s) : Kropp,John L. ; Dawson,William R.

Report Date : 1968

Pagination or Media Count : 16

Abstract : Fluorescence lifetimes (t) and fluorescence yields(P) of poly(methylmethacrylate) samples containing coronene-h12, coronene-d12, pyrene-h10, pyrene-d10, 1,2;5,6 dibenzanthracene, 1,2;7,8 dibenzanthracene, 1,2;3,4 dibenzanthracene, 1,2 benzcoronene and 1,12 benzperylene were measured. For all compounds studied, except coronene-h12 and coronene-d12, t decreases with increasing temperature. For all compounds except 1,12 benzperylene and 1,2;3,4 dibenzanthracene, P decreases proportionally with t so that the radiative lifetime (t) is temperature independent. For the two last mentioned compounds t varies with temperature. This may be due to the closeness of the p band to the lowest-lying alpha band. The activation energies of temperature dependent quenching of t are all similar. The quenching is related to Lin's theory of radiationless transitions and it is suggested that this temperature dependent quenching is due to S1 -- So transitions. (Author)

Descriptors :   (*AROMATIC COMPOUNDS, *FLUORESCENCE), (*POLYCYCLIC COMPOUNDS, *PHOSPHORESCENCE), PRESSURE, EXCITATION, RELAXATION TIME, ANTHRACENES, BAND SPECTRA, QUENCHING(INHIBITION), SOLID SOLUTIONS, ACRYLIC RESINS

Subject Categories : Radiation and Nuclear Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE