Confinement effects on the excess wing in the dielectric loss of glass-formers

Autor:	Johan Mattsson, Rikard Bergman, Christer Svanberg, Jan Swenson, Gustavo Ariel Schwartz
Rok vydání:	2003
Předmět:	Permittivity Arrhenius equation symbols.namesake Materials science Wing Condensed matter physics Dielectric strength Relaxation (NMR) symbols General Physics and Astronomy Dielectric loss Glass transition Dielectric spectroscopy
Zdroj:	Europhysics Letters (EPL). 64:675-681
ISSN:	1286-4854 0295-5075
DOI:	10.1209/epl/i2003-00615-y
Popis:	We present results from dielectric spectroscopy on four molecular glass-formers, both in bulk and in confined geometry. For systems exhibiting a well-resolved secondary (β) relaxation, the confinement induces a relative enhancement (compared to the main α relaxation) of the effective dielectric strength of the β process. In bulk systems without a well-separated β process a similar relative enhancement is found also for the contribution to the dielectric loss identified as the excess wing. The latter effect results in a bimodal loss, which suggests that the excess wing should be attributed to a relaxation process separate from, and thus not a feature of, the α relaxation. The results hence provide an explanation for the much debated excess wing often observed in the dielectric response of glass-formers.
Databáze:	OpenAIRE
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