ISSN:
0025-116X
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Fluorescence emission of amorphous poly(ethylene terephthalate) films at wavelengths larger than that of the excimer emission was investigated. A film thickness dependence of the excitation spectra for 360 nm emission was observed. For thick films (e.g., 280 μm), their excitation spectra for 380-460 nm emission showed excitation peaks in the region of 320-360 nm, and the intensity ratio of the 370 nm emission (excited by 290 nm radiation) to the 390 nm emission (excited by 340 nm radiation) decreased with increasing thickness of the film. Apparently, the 370 nm emission (excimer) and the 380-460 nm emission originate from different species of the excited state. From the studies of model systems, dilute solutions of dimethyl terephthalate in CHCl3-acetone and dimethyl terephthalate-PMMA in CHCl3, it was found that the excitation at 340 nm is related to a \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \pi \limits^* $\end{document} ← n transition. Fluorescence emission from the S1 (n-\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \pi \limits^* $\end{document}) state and the interaction between the C=O group and the phenylene π-electrons results in the fluorescence in the 380-460 nm region.
Zusätzliches Material:
9 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/macp.1991.021920616
