Structural relaxation in glasses: Numerical exploration of variables of Narayanaswamy and Moynihan's model

The accurate description of the relaxation phenomenon near the glass transition temperature allows a better interpretation of differential scanning calorimetry (DSC) curves, since it can be separated from other thermal effects such as crystallization, melting, and recrystallization. The structural r...

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Autores principales: Viollaz, P.E., Alzamora, S.M., Nieto, A.B.
Formato: JOUR
Materias:
DSC
Fictive temperature
Glass transition
Moynihan
Narayanaswamy
Crystallization
Heat transfer
Mathematical models
Melting
Relaxation processes
Structural relaxation
Glass
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_02608774_v56_n4_p393_Viollaz
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_02608774_v56_n4_p393_Viollaz2023-10-03T15:12:11Z Structural relaxation in glasses: Numerical exploration of variables of Narayanaswamy and Moynihan's model Viollaz, P.E. Alzamora, S.M. Nieto, A.B. DSC Fictive temperature Glass transition Moynihan Narayanaswamy Crystallization Glass transition Heat transfer Mathematical models Melting Relaxation processes Structural relaxation Glass The accurate description of the relaxation phenomenon near the glass transition temperature allows a better interpretation of differential scanning calorimetry (DSC) curves, since it can be separated from other thermal effects such as crystallization, melting, and recrystallization. The structural relaxation model of Narayanaswamy and Moynihan for thermorheological simple glasses was numerically explored for obtaining a grasp of the functional influence of the different parameters: i.e. relaxation enthalpy Δh, non-linear parameter x, amplitude exponential distribution parameter b, and pre-exponential parameter A. It is known that when the relationship between the velocity of heat transfer in the cooling run (qc) and the velocity of heating in the heating run (qh) is equal to unity, the curves obtained in a DSC suffer only an horizontal translation for different absolute values of cooling and heating rates. It was found in this work that this criterion can be generalized, and curves also overlap by means of a horizontal translation when qc/qh is a constant different from one, whichever the particular values of qc or qh will be. Finally, changes in the shape of the curves when using different values of qh and qc with a fixed qc/qh relationship can be used as an indicator of the occurrence of other phenomena (i.e. recrystallization, melting, etc.) in addition to structural relaxation. © 2002 Elsevier Science Ltd. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_02608774_v56_n4_p393_Viollaz
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic DSC
Fictive temperature
Glass transition
Moynihan
Narayanaswamy
Crystallization
Glass transition
Heat transfer
Mathematical models
Melting
Relaxation processes
Structural relaxation
Glass
spellingShingle DSC
Fictive temperature
Glass transition
Moynihan
Narayanaswamy
Crystallization
Glass transition
Heat transfer
Mathematical models
Melting
Relaxation processes
Structural relaxation
Glass
Viollaz, P.E.
Alzamora, S.M.
Nieto, A.B.
Structural relaxation in glasses: Numerical exploration of variables of Narayanaswamy and Moynihan's model
topic_facet DSC
Fictive temperature
Glass transition
Moynihan
Narayanaswamy
Crystallization
Glass transition
Heat transfer
Mathematical models
Melting
Relaxation processes
Structural relaxation
Glass
description The accurate description of the relaxation phenomenon near the glass transition temperature allows a better interpretation of differential scanning calorimetry (DSC) curves, since it can be separated from other thermal effects such as crystallization, melting, and recrystallization. The structural relaxation model of Narayanaswamy and Moynihan for thermorheological simple glasses was numerically explored for obtaining a grasp of the functional influence of the different parameters: i.e. relaxation enthalpy Δh, non-linear parameter x, amplitude exponential distribution parameter b, and pre-exponential parameter A. It is known that when the relationship between the velocity of heat transfer in the cooling run (qc) and the velocity of heating in the heating run (qh) is equal to unity, the curves obtained in a DSC suffer only an horizontal translation for different absolute values of cooling and heating rates. It was found in this work that this criterion can be generalized, and curves also overlap by means of a horizontal translation when qc/qh is a constant different from one, whichever the particular values of qc or qh will be. Finally, changes in the shape of the curves when using different values of qh and qc with a fixed qc/qh relationship can be used as an indicator of the occurrence of other phenomena (i.e. recrystallization, melting, etc.) in addition to structural relaxation. © 2002 Elsevier Science Ltd. All rights reserved.
format JOUR
author Viollaz, P.E.
Alzamora, S.M.
Nieto, A.B.
author_facet Viollaz, P.E.
Alzamora, S.M.
Nieto, A.B.
author_sort Viollaz, P.E.
title Structural relaxation in glasses: Numerical exploration of variables of Narayanaswamy and Moynihan's model
title_short Structural relaxation in glasses: Numerical exploration of variables of Narayanaswamy and Moynihan's model
title_full Structural relaxation in glasses: Numerical exploration of variables of Narayanaswamy and Moynihan's model
title_fullStr Structural relaxation in glasses: Numerical exploration of variables of Narayanaswamy and Moynihan's model
title_full_unstemmed Structural relaxation in glasses: Numerical exploration of variables of Narayanaswamy and Moynihan's model
title_sort structural relaxation in glasses: numerical exploration of variables of narayanaswamy and moynihan's model
url http://hdl.handle.net/20.500.12110/paper_02608774_v56_n4_p393_Viollaz
work_keys_str_mv AT viollazpe structuralrelaxationinglassesnumericalexplorationofvariablesofnarayanaswamyandmoynihansmodel
AT alzamorasm structuralrelaxationinglassesnumericalexplorationofvariablesofnarayanaswamyandmoynihansmodel
AT nietoab structuralrelaxationinglassesnumericalexplorationofvariablesofnarayanaswamyandmoynihansmodel
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