Regensburg 2002 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 7: Struktur und Dynamik in Polymersystemen II

CPP 7.3: Vortrag

Montag, 11. März 2002, 15:40–16:00, H38

Acoustic relaxation at the ideal glass transition versus Vogel-Fulcher-Tamann behavior — •Jörg Baller and Jan K. Krüger — FR 7.2 Experimentalphysik, Universität des Saarlandes, 66123 Saarbrücken

High-frequency sound velocities are a very sensitive probe for structural relaxation in amorphous solids. We reinvestigated the relaxation behaviour of Polyvinylacetate by measuring the clamped longitudinal modulus within the time domain near the thermal glass transition. Approaching the glass transition from higher temperatures, we observe an Arrhenius-like relaxation process with a clear cut-off at the glass transition temperature. The slowest relaxation time very close to the glass transition turned out to be about 107 seconds. Since we carried out our measurements with high (GHz) probe frequencies in thermal equilibrium,kinetic effects can be excluded. Consequences and comparisons with other results are presented.