Journal Article

FZJ-2016-07448

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Characteristic length scales of the secondary relaxations in glass-forming glycerol

Gupta, S. (Corresponding author)FZJ* ; Mamontov, E. ; Jalarvo, N.FZJ* ; Stingaciu, L.FZJ* ; Ohl, M.FZJ*

2016
Springer Berlin

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Please use a persistent id in citations: doi:10.1140/epje/i2016-16040-7

Abstract: We investigate the secondary relaxations and their link to the main structural relaxation in glass-forming liquids using glycerol as a model system. We analyze the incoherent neutron scattering signal dependence on the scattering momentum transfer, Q , in order to obtain the characteristic length scale for different secondary relaxations. Such a capability of neutron scattering makes it somewhat unique and highly complementary to the traditional techniques of glass physics, such as light scattering and broadband dielectric spectroscopy, which provide information on the time scale, but not the length scales, of relaxation processes. The choice of suitable neutron scattering techniques depends on the time scale of the relaxation of interest. We use neutron backscattering to identify the characteristic length scale of 0.7 Å for the faster secondary relaxation described in the framework of the mode-coupling theory (MCT). Neutron spin-echo is employed to probe the slower secondary relaxation of the excess wing type at a low temperature ( ∼ 1.13Tg . The characteristic length scale for this excess wing dynamics is approximately 4.7 Å. Besides the Q -dependence, the direct coupling of neutron scattering signal to density fluctuation makes this technique indispensable for measuring the length scale of the microscopic relaxation dynamics.

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Contributing Institute(s):

1. Neutronenstreuung (ICS-1)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)
3. JCNS-SNS (JCNS-SNS)

Research Program(s):

1. 551 - Functional Macromolecules and Complexes (POF3-551) (POF3-551)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)
3. 6215 - Soft Matter, Health and Life Sciences (POF3-621) (POF3-621)

Appears in the scientific report 2016

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; Nationallizenz ; No Authors Fulltext ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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