Long-term ageing behaviour in Ge–Se glasses

Golovchak, R.; Kozdraś, A.; Shpotyuk, O.; Kozyukhin, S. A.; Saiter, Jean‐Marc

doi:10.1007/s10853-009-3540-6

Cited by 31 publications

(29 citation statements)

References 22 publications

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“…3, the scan rate was 5 • C/min which is quite close to 3 • C/min used as a typical MDSC scan rate by Dash et al 2 At such low scan rates (2-5 • C/min), the conclusions drawn from MDSC and conventional DSC would be quite similar, which has been convincingly proved at the example of As/Ge-Se glasses. 3,5,6 The narrowing of glass transition range W as a result of physical aging or annealing was also observed previously in pure Se, 7 a number of Se-based glasses, 8,9 and even organic polymers. 10 Moreover, in As-Se glasses, this narrowing was accompanied by changes in the asymmetry of non-reversing heat flow (∆H nr ) measured at 2 • C/min scan rate after ∼20 years of dark storage at room temperature.…”

supporting

confidence: 75%

“…Additional argument comes from the fact, that formation of Se 8 crowns in supercooled liquid regime is thermodynamically favorable and irreversible process. 20,21 If it occurred as a result of aging, then the rejuvenation procedure (heating of the glass just above T g ), which is known to completely erase the effect of physical aging, 3,4,12 would become impossible. Even the structure of vitreous Se itself is a matter of ongoing discussions, pertaining to the controversies in the Se chains/rings ratio.…”

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confidence: 99%

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Comment on “Molecular origin of aging of pure Se glass: Growth of inter-chain structural correlations, network compaction, and partial ordering” [J. Chem. Phys. 146, 224506 (2017)]

Shpotyuk

Kozdraś

Saiter

et al. 2018

The Journal of Chemical Physics

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supporting

confidence: 75%

mentioning

confidence: 99%

Comment on “Molecular origin of aging of pure Se glass: Growth of inter-chain structural correlations, network compaction, and partial ordering” [J. Chem. Phys. 146, 224506 (2017)]

Shpotyuk

Kozdraś

Saiter

et al. 2018

The Journal of Chemical Physics

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“…ageing has been investigated in these chalcogenide networks [513,514,515]. Also, since the enthalpic loss is directly related to T g − T w , ageing is enhanced for compositions which have a lower T g (i.e.…”

Section: Chalcogenidesmentioning

confidence: 99%

Relaxation and physical aging in network glasses: a review

Micoulaut

2016

Rep. Prog. Phys.

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Abstract. Recent progresses in the description of glassy relaxation and ageing are reviewed for the wide class of network-forming materials such as GeO 2 , Ge x Se 1−x , silicates (SiO 2 -Na 2 O) or borates (B 2 O 3 -Li 2 O), all of them having an important usefulness in domestic, geological or optoelectronic applications. A brief introduction of the glass transition phenomenology is given, together with the salient features that are revealed both from theory and experiments. Standard experimental methods used for the characterization of the slowing down of the dynamics are reviewed. We then discuss the important role played by aspect of network topology and rigidity for the understanding of the relaxation of the glass transition, while also permitting analytical predictions of glass properties from simple and insightful models based on the network structure. We also emphasize the great utility of computer simulations which probe the dynamics at the molecular level, and permit to calculate various structure-related functions in connection with glassy relaxation and the physics of ageing which reveals the off-equilibrium nature of glasses. We discuss the notion of spatial variations of structure which leads to the picture of "dynamic heterogeneities", and recent results of this important topic for network glasses are also reviewed.PACS numbers: 61.43. Fs, 64.70.kj Relaxation and physical ageing in network glasses 2 Figure 1. Typical network-forming glasses: a) A stoichiometric glass former (SiO 2 , B 2 S 3 ) whose structure and network connectivity can be altered by the addition (b) of 2-fold coordinated atoms (usually chalcogens, S, Se) that lead to cross-linked chains. The structure can also be depolymerized (c) by the addition of a network modifier (alkali oxides or chalcogenides, Na 2 O, Li 2 S, etc.). Glassy dynamics depends strongly on the network topology, i.e. the way bonds and angles arrange to lead to a connected atomic network. Note that only chalcogenides can produce a mixture of these three kinds of basic networks, e.g. (1-x)Ge y Se 1−y -xAg 2 Se [2], and for the latter system x=0 corresponds to case (b), y=33% corresponds to case (c), and both conditions together (x=0,y=33 %) to case (a).

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“…From the other hand, the compositional behavior of long-and short-term physical ageing in the studied Ge x Se 100-x glasses clearly indicates the onset of reversibility window in a sense of non-ageing ability at x ≈ 20 [25]. As far as main microstructural mechanism of physical ageing in Se-rich glasses is connected with -Se-Se-Se-fragments [26], we should assume that backbone of glasses with x ≥ 20 does not include these fragments.…”

Section: Resultsmentioning

confidence: 91%

Cluster modeling of quasi‐adaptive phases in vitreous germanium selenides

Shpotyuk

Golovchak

Boyko

et al. 2010

Phys. Status Solidi (c)

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The developed cluster modeling approach based on ab‐initio calculations with RHF/6‐311G* basis set testifies absence of intermediate optimally‐constrained phase in binary Gex Se100‐x system within 20 ≤ x < 26 domain. It is shown, that character “outrigger raft” carcass is conserved for all glass compositions within expected reversibility window. Thus, the structure of binary Gex Se100‐x glasses can be described in terms of “chains crossing” model in case of x < 12, mixed “chains crossing” and “outrigger raft” models in case of 12 ≤ x < 20 and modified “outrigger raft” model in case of x ≥ 20. The expected reversibility window in binary Gex Se100‐x glasses is shown to be only quasi‐adaptive phase, based on “outrigger raft” structural motive with two edge‐ and four corner‐sharing tetrahedra interconnected by optimally‐constrained Ge‐Se‐Se‐Ge bridges with extra Se atoms in ring‐like configurations replaced Se‐Se dimers. The results of quantum mechanics modeling are confirmed well by high‐resolution X‐ray photoelectron spectroscopy measurements in this system. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Long-term ageing behaviour in Ge–Se glasses

Cited by 31 publications

References 22 publications

Comment on “Molecular origin of aging of pure Se glass: Growth of inter-chain structural correlations, network compaction, and partial ordering” [J. Chem. Phys. 146, 224506 (2017)]

Comment on “Molecular origin of aging of pure Se glass: Growth of inter-chain structural correlations, network compaction, and partial ordering” [J. Chem. Phys. 146, 224506 (2017)]

Relaxation and physical aging in network glasses: a review

Cluster modeling of quasi‐adaptive phases in vitreous germanium selenides

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