1. Excess wing and Johari–Goldstein relaxation in binary mixtures of glass formers
- Author
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Pierangelo Rolla, Mauro Lucchesi, Khadra Kessairi, Simone Capaccioli, Daniele Prevosto, Department of Physics, Okayama University, Department of Physics University of Pisa, University of Pisa - Università di Pisa, and CNR-INFM Soft
- Subjects
DYNAMICS ,SUPERCOOLED LIQUIDS ,Thermodynamics ,02 engineering and technology ,01 natural sciences ,Spectral line ,chemistry.chemical_compound ,0103 physical sciences ,Organic chemistry ,010306 general physics ,Coupling ,SPECTROSCOPY ,Wing ,Chemistry ,Intermolecular force ,Quinaldine ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,3. Good health ,Physical Sciences ,BETA-RELAXATION ,Relaxation (physics) ,Dielectric loss ,ALPHA-RELAXATION ,0210 nano-technology ,Glass transition - Abstract
International audience; Dielectric loss spectra of pure quinaldine and tert-butylpyridine and their mixtures with tri-styrene are presented. The pure systems present an excess wing and no secondary peaks in the temperature interval from above to well below the glass transition. However, when mixed in low concentration with tri-styrene the excess wing is replaced by a distinct secondary peak. This distinct process can be identified as a Johari-Goldstein relaxation within the Coupling Model interpretation. In the frame of the Coupling Model the transition from the relaxation scenario with the excess wing to that with a distinct secondary peak is related to the increase of intermolecular constraints. In our case this increase of constraints is due to the low mobility component of the mixture (tri-styrene).
- Published
- 2007
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