Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 35: Poster: Glasses and Glass Transition
CPP 35.2: Poster
Mittwoch, 24. März 2010, 17:30–19:00, Poster B2
Structural Relaxation in Disordered Solids Below Tg: Study by Thermal-Cycling Single-Molecule Spectroscopy — Yuri G. Vainer1, Ivan Yu. Eremchev1, Andrei V. Naumov1, and •Lothar Kador2 — 1Institute for Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow Reg., 142190, Russia — 2University of Bayreuth, Institute of Physics and Bayreuther Institut für Makromolekülforschung (BIMF), 95440 Bayreuth, Germany
Structural relaxation processes in disordered solids have been studied between 4.5 K and the glass transition with single-molecule spectroscopy and thermal-cycling experiments. The investigated systems are the amorphous polymer polyisobutylene (PIB) doped with a substituted terrylene (TBT) and the disordered crystal ortho-dichlorobenzene (o-DCB) doped with terrylene (Tr). Irreversible changes of single-molecule spectra were observed and attributed to relaxation processes in the local environment of the chromophore molecules. The effects of these processes on the individual parameters of low-energy excitations in the glass matrix (two-level systems and quasi-localized low-frequency vibrational modes) were analyzed as a function of temperature for the system TBT/PIB. Surprisingly, a large number of relaxation processes take place far below Tg. The data indicate also that the activation energies of the relaxations are distributed non-uniformly in space.