Triplet Energy Migration in Poly(4-methacryloylbenzophenone-co-methyl methacrylate) Films: Temperature Dependence and Chromophore Concentration Dependence

Autor:	William R. Liebe, Akira Tsuchida, Kyoji Tsubakiyama, Masahide Yamamoto, Richard D. Burkhart
Rok vydání:	1996
Předmět:	Polymers and Plastics Chemistry Organic Chemistry Analytical chemistry Chromophore Atmospheric temperature range Photochemistry Methacrylate Inorganic Chemistry chemistry.chemical_compound Reaction rate constant Excited state Materials Chemistry Benzophenone Triplet state Methyl methacrylate
Zdroj:	Macromolecules. 29:1589-1594
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma9509671
Popis:	Transient decays of triplet−triplet (TT) absorption of excited triplet benzophenone (BP) chromophore in poly(4-methacryloylbenzophenone-co-methyl methacrylate) (BPX, X is the mol % of BP, X = 1−100) films were studied by laser photolysis with a kinetic scheme involving a TT annihilation in a wide temperature range (20−240 K). The rate constant of the TT annihilation was analyzed by a diffusion model of the BP triplet state. The calculated diffusion coefficient (D) increased greatly with the increase of temperature and BP concentration in the BPX sample from 1 × 10-11 cm2 s-1 (20 K, X = 1) to 5 × 10-7 cm2 s-1 (240 K, X = 100). The steep increase in D was observed at the average BP distance less than 1.2 nm and above ca. 150 K. This temperature corresponds to Tγ of poly(methyl methacrylate), α-methyl rotation.
Databáze:	OpenAIRE
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