Broadband dielectric spectroscopy and aging of glass formers

Wehn, R.; Lunkenheimer, P.; Loidl, A.

doi:10.1016/j.jnoncrysol.2007.03.023

Cited by 32 publications

(30 citation statements)

References 75 publications

(137 reference statements)

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“…Above T g (indicated by the arrows), s b (T) shows a transition into a stronger temperature dependence than at T < T g . Similar behavior was also found in various other glass formers [3,6,48]. It is interesting that the b-dynamics for all three glycols approaches each other with increasing temperature.…”

Section: The Secondary Relaxationsupporting

confidence: 80%

Glassy dynamics in mono-, di- and tri-propylene glycol: From the α- to the fast β-relaxation

Köhler

Lunkenheimer

Goncharov

et al. 2010

Journal of Non-Crystalline Solids

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a b s t r a c tWe present a thorough characterization of the glassy dynamics of three propylene glycols (mono-, di-and trimer) by broadband dielectric spectroscopy. By covering a frequency range of more than 15 decades, we have access to the entire variety of dynamic processes typical for glassy dynamics. These results add three more molecular glass formers to the sparse list of materials for which real broadband spectra, including the region of the fast b-process, are available. Some first analyses of the various observed dynamic processes are provided.

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Section: The Secondary Relaxationsupporting

confidence: 80%

Glassy dynamics in mono-, di- and tri-propylene glycol: From the α- to the fast β-relaxation

Köhler

Lunkenheimer

Goncharov

et al. 2010

Journal of Non-Crystalline Solids

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“…Lunkenheimer and co-workers [33][34][35] recently studied aging also by monitoring the dielectric loss. They found that the relaxation curves R͑t͒ to a good approximation may be described by a stretched-exponential relaxation function which, as a new feature, introduces a time-dependent characteristic time ͑t͒ : R͑t͒ = exp͓−͑t / ͑t͒͒ ␤ ͔.…”

Section: The Internal Clock Hypothesismentioning

confidence: 99%

“…Moreover, for a viscous liquid of molecules with a permanent dipole moment, a frequency range exists in which the dielectric loss changes considerably for small temperature variations. The dielectric loss was used previously for monitoring aging by several groups, e.g., by Johari, 25 Schlosser and Schönhals, 26 Alegria et al, [27][28][29] Leheny et al, 30,31 Cangialosi et al, 32 Lunkenheimer et al, [33][34][35] D'Angelo et al, 36 and Serghei and Kremer. 37 This paper presents ideal aging experiments on five organic liquids with both temperature up and down jumps ͑Sec.…”

Section: Introductionmentioning

confidence: 99%

Physical aging of molecular glasses studied by a device allowing for rapid thermal equilibration

Hecksher

Olsen

Niss

et al. 2010

The Journal of Chemical Physics

101

106

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Aging to the equilibrium liquid state of organic glasses is studied. The glasses were prepared by cooling the liquid to temperatures just below the glass transition. Aging following a temperature jump was studied by measuring the dielectric loss at a fixed frequency using a microregulator in which temperature is controlled by means of a Peltier element. Compared to conventional equipment, the new device adds almost two orders of magnitude to the span of observable aging times. Data for the following five glass-forming liquids are presented: dibutyl phthalate, diethyl phthalate, 2,3-epoxy propyl-phenyl-ether, 5-polyphenyl-ether, and triphenyl phosphite. The aging data were analyzed using the Tool-Narayanaswamy formalism. The following features are found for all five liquids: (1) The liquid has an "internal clock," a fact that is established by showing that aging is controlled by the same material time that controls the dielectric properties. (2) There are no so-called expansion gaps between the long-time limits of the relaxation rates following up and down jumps to the same temperature. (3) At long times, the structural relaxation appears to follow a simple exponential decay. (4) For small temperature steps, the rate of the long-time exponential structural relaxation is identical to that of the long-time decay of the dipole autocorrelation function.

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“…The lines are fits with the sum of a Havriliak-Negami and a Cole-Cole function. The data below 120 GHz have been previously published in[20].…”

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confidence: 99%

High-frequency dynamics of type B glass formers investigated by broadband dielectric spectroscopy

Kastner

Köhler

Goncharov

et al. 2011

Journal of Non-Crystalline Solids

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a b s t r a c t a r t i c l e i n f oWe present the results of broadband dielectric spectroscopy on two glass formers with strong JohariGoldstein β-relaxations. In addition to the α-and β-relaxation dynamics, the extension of the spectra up to 1 THz also allows revealing information on the fast β-process in this class of materials. There is clear evidence for a fast process contributing in the region of the high-frequency loss minimum, which is analyzed in terms of the idealized mode-coupling theory.

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Broadband dielectric spectroscopy and aging of glass formers

Cited by 32 publications

References 75 publications

Glassy dynamics in mono-, di- and tri-propylene glycol: From the α- to the fast β-relaxation

Glassy dynamics in mono-, di- and tri-propylene glycol: From the α- to the fast β-relaxation

Physical aging of molecular glasses studied by a device allowing for rapid thermal equilibration

High-frequency dynamics of type B glass formers investigated by broadband dielectric spectroscopy

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