Accession Number : AD0678508

Title :   TEMPERATURE EFFECTS ON THE PHOSPHORESCENCE OF AROMATIC HYDROCARBONS IN POLY (METHYL METHACRYLATE),

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Jones,Peter F. ; Siegel,Seymour

Report Date : SEP 1968

Pagination or Media Count : 29

Abstract : Temperature effects on the phosphorescence lifetimes and phosphorescence intensities of naphthalene, phenanthrene, pyrene, biphenyl, and the perdeuterated analogs of these four molecules were measured with the use of poly (methyl methacrylate) (PMM) as a rigid solvent matrix. The phosphorescence lifetimes of these molecules decrease by only 13 to 37 percent upon warming from 77K to room temperature. On the basis of direct measurements of the permeability of PMM to oxygen, we conclude that oxygen quenching is not responsible for the observed temperature effects on the phosphorescence lifetimes. Although we cannot exclude the possibility that the rate constants for both radiative and nonradiative decay vary with temperature, we show that our results are consistent with an analysis that assumes that only the nonradiative rate constant is temperature dependent. On the basis of this analysis, we estimate an activation energy of 500 plus or minus 100/cm for the thermally activated nonradiative decay mode. (Author)

Descriptors :   (*PHOSPHORESCENCE, *AROMATIC COMPOUNDS), TEMPERATURE, ACRYLIC RESINS, POLYMERIZATION, SOLVENTS, OXYGEN, QUENCHING(INHIBITION), HEAT OF ACTIVATION

Subject Categories : Radiation and Nuclear Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE