Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 3: Polymer Materials
CPP 3.2: Talk
Monday, March 27, 2006, 10:15–10:30, ZEU 114
The Chemical Glass Transition as seen by High Performance Brillouin spectroscopy: Epoxies and Polyurethanes, a comparison — •Martine Philipp1, Christelle Vergnat2, Ravi Bactavatchalou2, Jörg Baller1, Wulf Possart2, Ulrich Müller2, Didier Rouxel3, Roland Sanctuary1, and Jan K. Krüger2 — 1Laboratoire Européen de Recherche Universitaire Saarland-Lorraine-Luxembourg Université de Luxembourg 162a, avenue de la Faiencerie L-1511 Luxembourg — 2Universität des Saarlandes D-66123 Saarbrücken — 3Université de Nancy I, Bd des Aiguillettes F-54506 Vandoeuvre
The nature of the glass transition and the nature of the glassy state are still a matter of debate. There are two contradictory hypothesis which do compete: The kinetic hypothesis and the transition hypothesis. According to the kinetic hypothesis the glass transition is due to a cross-over of the relevant intrinsic alpha-relaxation time with the time constant of the measurement probe in addition to the patience of the experimentalist. It is therefore of great interest to investigate a type of glass transition which by definition does not suffer from such a cross-over between the experimental time scale and the intrinsic relaxation times. For that purpose we present in this contribution investigations of the chemically induced glass transition. As model substances we have chosen the two reactive polymers: epoxy and polyurethane. As a sensitive probe for the detection of the chemical glass transition we use so-called mode-Grüneisen parameters. These parameters have been measured with high performance Brillouin spectroscopy. The results will be compared with other physical quantities as the specific heat and the refractive index.