How to Distinguish Nonexponentiality and Nonlinearity in Isothermal Structural Relaxation of Glass-Forming Materials
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F24%3A39922227" target="_blank" >RIV/00216275:25310/24:39922227 - isvavai.cz</a>
Result on the web
<a href="https://pubs.acs.org/doi/10.1021/acs.jpcb.4c02226" target="_blank" >https://pubs.acs.org/doi/10.1021/acs.jpcb.4c02226</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acs.jpcb.4c02226" target="_blank" >10.1021/acs.jpcb.4c02226</a>
Alternative languages
Result language
angličtina
Original language name
How to Distinguish Nonexponentiality and Nonlinearity in Isothermal Structural Relaxation of Glass-Forming Materials
Original language description
The nonexponentiality and nonlinearity are two essential features of the structural relaxation in any glass-forming material, which seem to be inextricably bound together by the material time. It is shown that the temperature down-jump and up-jump experiments of the same magnitude Delta T = T-0 - T to the same temperature T provide a clue for their separation. The isothermal structural relaxation can be quantified using the stabilization period on the logarithmic time scale log(t(m)/t(0)). It is described as the sum of the nonexponentiality term 1.181/ss and the nonlinearity term (sigma/2.303)Delta T for the temperature down-jump, and as their difference for the temperature up-jump. The material parameter sigma = -(partial derivative ln tau/partial derivative T-f)(i) quantifies variation of the relaxation time with structural changes at the inflection point of the relaxation curve and is formulated for the most widely used phenomenological models. The asymmetry of approach to equilibrium after the temperature down-jump and up-jump was first described by Kovacs in 1963. A detailed analysis of this asymmetry is provided, and a simple method for the estimation of the parameters characterizing the nonexponentiality (ss) and nonlinearity (sigma) is proposed. The applicability of this method is tested using previously reported isothermal experimental data as well as calculated data for aging of polymers and other glass-forming materials. This concept illuminates differences in structural relaxation kinetics in a simple and consistent way that can be useful in the design of novel materials and the evaluation of their physical aging treatment.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10403 - Physical chemistry
Result continuities
Project
—
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2024
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of Physical Chemistry B
ISSN
1520-6106
e-ISSN
1520-5207
Volume of the periodical
128
Issue of the periodical within the volume
33
Country of publishing house
US - UNITED STATES
Number of pages
10
Pages from-to
8074-8083
UT code for WoS article
001287552300001
EID of the result in the Scopus database
2-s2.0-85200804347