Chain-length-dependent relaxation scenarios in an oligomeric glass-forming system: from merged to well-separated alpha and beta loss peaks

We have studied the relaxation dynamics of a homologous series of propylene glycol based dimethyl ethers in the supercooled regime by means of broadband dielectric spectroscopy. The system is chosen in order to minimize changes of the intermolecular interactions with varying molecular weight, M. A g...

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Bibliographic Details
Published inPhysical review letters Vol. 90; no. 7; p. 075702
Main Authors Mattsson, J, Bergman, R, Jacobsson, P, Börjesson, L
Format Journal Article
LanguageEnglish
Published United States 21.02.2003
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Summary:We have studied the relaxation dynamics of a homologous series of propylene glycol based dimethyl ethers in the supercooled regime by means of broadband dielectric spectroscopy. The system is chosen in order to minimize changes of the intermolecular interactions with varying molecular weight, M. A gradual transformation from a scenario of well-separated to one of merged alpha and beta loss peaks was observed with decreasing M. The results give strong evidence for the currently debated excess wing being due to an underlying beta relaxation. The study suggests that the main difference between glass formers with and without excess wings is the relaxation time at the merging temperature.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.90.075702