Effect of thermodynamic history on secondary relaxation in the glassy state

Sharifi, Soheil; Prevosto, D.; Capaccioli, S.; Lucchesi, M.; Paluch, Marian

doi:10.1016/j.jnoncrysol.2007.03.044

Cited by 15 publications

(14 citation statements)

References 25 publications

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“…[54][55][56][57]), experimental measurements (for example Refs. [11,13,27,38,[58][59][60][61][62][63][64][65]), and molecular dynamics simulations (for example see [66,67]). For experimental measurements, there are many examples and only a few are chosen and discussed here.…”

Section: Connection Between Structural and Jg Relaxation Timementioning

confidence: 99%

Does the entropy and volume dependence of the structural α-relaxation originate from the Johari–Goldstein β-relaxation?

Prevosto

Capaccioli

Lucchesi

et al. 2009

Journal of Non-Crystalline Solids

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Section: Connection Between Structural and Jg Relaxation Timementioning

confidence: 99%

Does the entropy and volume dependence of the structural α-relaxation originate from the Johari–Goldstein β-relaxation?

Prevosto

Capaccioli

Lucchesi

et al. 2009

Journal of Non-Crystalline Solids

Self Cite

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“…At ambient pressure, a structural, α-, process is visible above the glass transition temperature, T g , and for temperatures below T g two secondary processes, βand γ -, are present. 13,15,26 In the following study an extensive investigation of the pressure and temperature dependence of the β-relaxation in the glassy state is reported. 15 One of the secondary processes, that appearing at lower frequencies and being named β-relaxation, has been previously recognized to be a secondary Johary-Goldstein process.…”

Section: Resultsmentioning

confidence: 99%

“…The data of the structural relaxation are obtained by measurements in the supercooled liquid state previously published. 26,36 Moreover, we have to mention that, even in the case of JG process, the activation volume has an abrupt reduction on entering in the glassy state. 27 and 28).…”

Section: A Temperature Dependence Of Activation Volumementioning

confidence: 99%

“…In other words, it reflects the cooperativity among different sub-groups of the same molecule. 13,15,26 It is suggested that the activation entropy can be used as an indicator to understand the microscopic origin of secondary processes in a particular system. [18][19][20][21][22][23][24]48 The β-process of PPGE is of the JG type, i.e.…”

Section: B Pressure Dependence Of Activation Entropy and Enthalpymentioning

confidence: 99%

“…In this work, we investigated the pressure and temperature dependence of the relaxation dynamics in the epoxy system poly [(phenyl glycidyl ether)-co-formaldehyde] (PPGE), 15,25,26 with particular focus on the intermediate secondary process. Experimental results on such a process, in the following named the β-process, have already been reported, supporting its classification as a JG secondary process.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Temperature and pressure dependence of secondary process in an epoxy system

Sharifi

Capaccioli

Lucchesi

et al. 2011

The Journal of Chemical Physics

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Dielectric spectroscopy as a function of temperature and pressure was used to study the secondary relaxation in poly [(phenyl glycidyl ether)-co-formaldehyde] at hydrostatic pressure up to 600 MPa and at different temperatures between 315 and 243 K. From the analysis of the isothermal measurements, we observe that the activation volume of the secondary relaxation has nonmonotonic temperature dependence with a maximum at the temperature of the glass transition at ambient pressure. An interpretation in terms of mean hole volume dispersion is proposed based on literature data. Moreover, from isobaric data, we studied the effect of pressure on activation entropy and enthalpy of the secondary relaxation evidencing its local nature but also the presence of a certain complexity of the motion, which supports the idea that this process reflects the motion of a large part of the molecule.

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Secondary molecular mobility in amorphous ethyl cellulose: Aging effects and degree of co‐operativity

Diogo¹,

Ramos²

2009

J Polym Sci B Polym Phys

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The secondary relaxations in amorphous ethyl cellulose are studied using thermally stimulated depolarization currents (TSDCs) in the temperature region from 165 °C (108 K) up to 145 °C (418 K). The influence of aging on the current peaks of the secondary relaxation is discussed, and it is concluded that some modes of motion of this mobility are aging independent, while others are affected by aging. A particular attention is focused on the discussion of the degree of co‐operativity of the motional modes of the secondary relaxation. The conclusion to be driven from the obtained TSDC results is that the aging‐independent motional modes, as well as those that are aging dependent, do not show any appreciable co‐operative character. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 820–829, 2009

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Effect of thermodynamic history on secondary relaxation in the glassy state

Cited by 15 publications

References 25 publications

Does the entropy and volume dependence of the structural α-relaxation originate from the Johari–Goldstein β-relaxation?

Does the entropy and volume dependence of the structural α-relaxation originate from the Johari–Goldstein β-relaxation?

Temperature and pressure dependence of secondary process in an epoxy system

Secondary molecular mobility in amorphous ethyl cellulose: Aging effects and degree of co‐operativity

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