Fragile Glass Formers: Evidence for a New Paradigm, and a New Relation to Strong Liquids

Angell, C. Austen

doi:10.1002/9781118202470.ch7

Cited by 5 publications

(7 citation statements)

References 127 publications

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Section: Introductionmentioning

confidence: 61%

“…The coefficient of ln(K ls ) in (21), called g(), becomes equal to 1 at the homogeneous nucleation temperature given in (13) and the equation (11) is respected. Homogeneously-condensed clusters of natoms act as growth nuclei at a temperature generally higher than the homogeneous nucleation temperatures T 1 and T 2 of liquids.…”

Section: Critical Supercluster Homogeneous Nucleation Temperature Andmentioning

confidence: 99%

“…Three situations are met when the two critical energy barriers in (21) and (22) are compared. The growth around nuclei can be very rapid if G* 2ls /k B T given in (21) is smaller than G* nm /k B T given in (22). The steady-state nucleation time t sn (T) is calculated with (23) knowing the sample volume v. This is the case for glass-forming melt crystallization above T g .…”

Section: Critical Supercluster Homogeneous Nucleation Temperature Andmentioning

confidence: 99%

“…The Kauzmann temperature would be the true glass transition at equilibrium [20]. Angell showed how such a theory for fragile liquids fits into a phenomenological scheme covering all glass formers [21]. A criterion analogous to the Lindemann criterion of melting was established for the glass-liquid transition [22].…”

Section: Introductionmentioning

confidence: 99%

“…The formation of the stable-glass phase in fragile glasses is accompanied by an exothermic latent heat which does not exist in strong glasses. The glass transition in strong liquids is a true liquid-liquid transformation without hidden latent heat as already shown in various models [6][7][8][10][11][12][13][14][15][19][20][21][22]]. The classical model of crystal nucleation is completed by adding an unknown enthalpy saving in the Gibbs free energy change equal to ls ×H m = V m ×p for a supercluster formation, where p is a complementary Laplace pressure acting on the growth critical nucleus [27].…”

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confidence: 99%

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Fragile-to-fragile liquid transition at Tg and stable-glass phase nucleation rate maximum at the Kauzmann temperature TK

Tournier

2014

Physica B: Condensed Matter

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An undercooled liquid is unstable. The driving force of the glass transition at T g is a change of the undercooled-liquid Gibbs free energy. The classical Gibbs free energy change for a crystal formation is completed including an enthalpy saving. The crystal growth critical nucleus is used as a probe to observe the Laplace pressure change p accompanying the enthalpy changeV m ×p at T g where V m is the molar volume. A stable glass-liquid transition model predicts the specific heat jump of fragile liquids at T ≤ T g , the Kauzmann temperature T K where the liquid entropy excess with regard to crystal goes to zero, the equilibrium enthalpy between T K and T g , the maximum nucleation rate at T K of superclusters containing magic atom numbers, and the equilibrium latent heats at T g and T K . Strongto-fragile and strong-to-strong liquid transitions at T g are also described and all their thermodynamic parameters are determined from their specific heat jumps. The existence of fragile liquids quenched in the amorphous state, which do not undergo liquid-liquid transition during heating preceding their crystallization, is predicted. Long ageing times leading to the formation at T K of a stable glass composed of superclusters containing up to 147 atoms, touching and interpenetrating, are evaluated from nucleation rates. A fragile liquid-liquid transition occurs at T g without stable-glass formation while a strong glass is stable after transition.

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Section: Introductionmentioning

confidence: 61%

Section: Critical Supercluster Homogeneous Nucleation Temperature Andmentioning

confidence: 99%

Section: Critical Supercluster Homogeneous Nucleation Temperature Andmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Fragile-to-fragile liquid transition at Tg and stable-glass phase nucleation rate maximum at the Kauzmann temperature TK

Tournier

2014

Physica B: Condensed Matter

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Structural Relaxation

Hodge

2019

Classical Relaxation Phenomenology

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Vapor Condensed and Supercooled Glassy Nanoclusters

Bowles

2016

ACS Nano

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We use molecular simulation to study the structural and dynamic properties of glassy nanoclusters formed both through the direct condensation of the vapor below the glass transition temperature, without the presence of a substrate, and via the slow supercooling of unsupported liquid nanodroplets. An analysis of local structure using Voronoi polyhedra shows that the energetic stability of the clusters is characterized by a large, increasing fraction of bicapped square antiprism motifs. We also show that nanoclusters with similar inherent structure energies are structurally similar, independent of their history, which suggests the supercooled clusters access the same low energy regions of the potential energy landscape as the vapor condensed clusters despite their different methods of formation. By measuring the intermediate scattering function at different radii from the cluster center, we find that the relaxation dynamics of the clusters are inhomogeneous, with the core becoming glassy above the glass transition temperature while the surface remains mobile at low temperatures. This helps the clusters sample the highly stable, low energy structures on the potential energy surface.Our work suggests the nanocluster systems are structurally more stable than the ultrastable glassy thin films, formed through vapor deposition onto a cold substrate, but the 1 arXiv:1702.05208v1 [cond-mat.soft]

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Fragile Glass Formers: Evidence for a New Paradigm, and a New Relation to Strong Liquids

Cited by 5 publications

References 127 publications

Fragile-to-fragile liquid transition at Tg and stable-glass phase nucleation rate maximum at the Kauzmann temperature TK

Fragile-to-fragile liquid transition at Tg and stable-glass phase nucleation rate maximum at the Kauzmann temperature TK

Structural Relaxation

Vapor Condensed and Supercooled Glassy Nanoclusters

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