Berlin 2008 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 8: Glasses II (joint session DF/DY)

DF 8.3: Vortrag

Dienstag, 26. Februar 2008, 15:00–15:15, EB 407

Fluorescence lifetime fluctuations and molecular reorientation of single molecules as observables of the dynamics in supercooled poly(methyl acrylate) — Renaud Vallée², •Gerald Hinze¹, Taoufik Rohand², Noel Boens², Wim Dehaen², and Thomas T. Basché¹ — ¹Institute of Physical Chemistry, Johannes-Gutenberg University, Mainz, Germany — ²Department of Chemistry , Katholieke Universiteit Leuven, 3001 Leuven, Belgium

The dynamics of supercooled poly(methyl acrylate) has been explored on a nanoscale by tracking single fluorescing molecules as local reporter. We could follow the molecular orientation and the fluctuating fluorescence lifetime of single dyes in time. To meet the requirements of high photostability and a very high quantum yield, custom-built BODIPY dyes have been used. Experiments were performed in bulk sample to prevent interface effects.

While the rotational dynamics of the dyes strongly depends on the interaction between matrix and the probe molecules, the fluorescence lifetime could alter solely by matrix fluctuations without structural dynamics of the dye. We have analyzed the fluctuations by means of correlation functions and discuss their relationship to the dynamics of the supercooled matrix.