Neutron Spin Echo Study of Dynamic Correlations Near Liquid-Glass Transition

Mezei, F.; Knaak, W.; Faragó, B.

doi:10.1088/0031-8949/1987/t19b/007

Cited by 110 publications

(61 citation statements)

References 22 publications

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“…2b and Fig. 5) and strongly resembles that reported in few coherent neutron scattering studies of polymeric supercooled liquids [61][62][63] . In these systems, the dynamics is affected by two main contributions, which lead to an oscillatory behaviour of t(Q) with a first maximum in correspondence with a weak structural prepeak, followed by a second one associated with the de Gennes narrowing at the main sharp diffraction peak.…”

Section: Resultssupporting

confidence: 87%

“…The microscopic relaxation dynamics is in addition significantly affected by the presence of ion-conducting pathways, presenting a peculiar increase in the relaxation time at the characteristic distance between the sodium diffusion channels in the network, in agreement with high temperature simulation in molten silicates 28,31 . A similar Q dependence has been reported also in few other supercooled liquids, but for very high temperatures and for time scales more than 10 orders of magnitude faster than those here probed 62,63 , suggesting a more complex origin 64,65 .…”

Section: Discussionsupporting

confidence: 89%

“…2b for a comparison between t(Q max , T) and t(Q 1 , T)). On the other hand, the shoulder around Q max is reminiscent of the de Gennes-like narrowing observed in coherent neutron scattering experiments of supercooled liquids [60][61][62][63] . This feature is better evidenced by comparing t(Q) with the quantity S(Q)/Q 2 as shown in Fig.…”

Section: Resultsmentioning

confidence: 77%

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Revealing the fast atomic motion of network glasses

Baldi²,

et al. 2014

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Still very little is known on the relaxation dynamics of glasses at the microscopic level due to the lack of experiments and theories. It is commonly believed that glasses are in a dynamical arrested state, with relaxation times too large to be observed on human time scales. Here we provide the experimental evidence that glasses display fast atomic rearrangements within a few minutes, even in the deep glassy state. Following the evolution of the structural relaxation in a sodium silicate glass, we find that this fast dynamics is accompanied by the absence of any detectable aging, suggesting a decoupling of the relaxation time and the viscosity in the glass. The relaxation time is strongly affected by the network structure with a marked increase at the mesoscopic scale associated with the ion-conducting pathways. Our results modify the conception of the glassy state and asks for a new microscopic theory.

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Section: Resultssupporting

confidence: 87%

Section: Discussionsupporting

confidence: 89%

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Revealing the fast atomic motion of network glasses

Baldi²,

et al. 2014

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“…Obviously, one expects that studying the evolution of the glassy dynamics within the GHz-band can reveal to us some essential features of this phenomenon. Beginning with neutron scattering work [3,4] it became possible during the past ten years to explore anomalous dynamics in the GHz-band and, indeed, a whole series of new phenomena has been discovered. Furthermore, a microscopic theory for the evolution of the glassy dynamics, called the mode-coupling theory (MCT), was proposed, whose results correlate reasonably with some of the experimental facts.…”

Section: Wgötzementioning

confidence: 99%

“…Equations (1)(2)(3) are the basis of the MCT. One can generalize the theory to a treatment of mixtures [10,11] or of non-spherical molecules [12,13], but these extensions will not be considered in the following.…”

Section: The Basic Version Of the Mode-coupling Theorymentioning

confidence: 99%

The Essentials of the Mode-Coupling Theory for Glassy Dynamics

Gotze¹

1998

Condens. Matter Phys.

101

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The essential results of the mode-coupling theory for the evolution of structural relaxation in simple liquids such as the Debye-Waller-factor anomaly, the critical decay, von Schweidler's law, the α -and β -relaxation scaling, the appearance of two divergent time scales, and Kohlrausch's law for the α -process are explained, and their relevance to the understanding of experiments in glass-forming systems is described. : 64.70.Pf, 61.20.Lc In memoriam: I first met Dmitrii Nikolaevich Zubarev in 1969, when I came to Moscow to work with his team at the Steklov-Institute. Since then we met regularly. I always enjoyed discussing with him many open problems in statistical physics and I learned a lot from his unbiased and well contemplated views on various issues. I like to remember his gentleness, his warm hospitality, and the conversations with him on non-scientific matters. I dedicate this article to the memory of Dmitrii Nikolaevich with gratitude. Key words: mode-coupling theory, structural relaxation, glassy dynamics, bifurcation dynamics PACS

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Inelastic Neutron Scattering Experiments on Van der Waals Glasses — A Test of Recent Microscopic Theories of the Glass Transition

Bartsch

Fujara

Kiebel

et al. 1989

Ber Bunsenges Phys Chem

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By performing incoherent inelastic neutron scattering experiments on the Van der Waals glass o‐terphenyl we tested predictions made by a recent microscopic theory — the mode coupling theory of the glass transition. In agreement with theory we find — besides the structural relaxation or α‐process which follows a Kohlrausch‐Williams‐Watts behaviour — the existence of a secondary relaxation process which shows very unusual neutron scattering features. This secondary or ß‐process leads to an anomalous decrease of the Debye‐Waller factor which can be interpreted in terms of a critical (Tc‐T)‐behaviour as predicted by theory. According to mode coupling theory this behaviour should be connected to a critical slowing down of the density fluctuations in the vicinity of a critical temperature Tc which is situated typically 30 to 150 degrees above the caloric glass transition temperature Tg. We find our neutron scattering data to be compatible with the predictions of theory leading to a value of Tc that is situated well above Tg i.e. in the range 285–295 K as compared to Tg = 243 K. This agrees well with a value of Tc = 290 K derived independently by use of a power law, suggested by theory to hold for the behaviour of the viscosity at temperatures higher than Tc.

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Neutron Spin Echo Study of Dynamic Correlations Near Liquid-Glass Transition

Cited by 110 publications

References 22 publications

Revealing the fast atomic motion of network glasses

Revealing the fast atomic motion of network glasses

The Essentials of the Mode-Coupling Theory for Glassy Dynamics

Inelastic Neutron Scattering Experiments on Van der Waals Glasses — A Test of Recent Microscopic Theories of the Glass Transition

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