scholarly journals Evolution of collective motion in a model glass-forming liquid during physical aging

2013 ◽  
Vol 138 (12) ◽  
pp. 12A528 ◽  
Author(s):  
Amit Shavit ◽  
Jack F. Douglas ◽  
Robert A. Riggleman
Keyword(s):  
Physical Aging ◽  
Collective Motion ◽  
Glass Forming ◽  
Model Glass

scholarly journals Physical Aging Behavior of a Glassy Polyether

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 954
Author(s):  
Xavier Monnier ◽  
Sara Marina ◽  
Xabier Lopez de Pariza ◽  
Haritz Sardón ◽  
Jaime Martin ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Physical Aging ◽  
Glassy State ◽  
Aging Behavior ◽  
Scanning Calorimetry ◽  
Narrow Temperature Range ◽  
Glass Forming ◽  
Fast Scanning Calorimetry

The present work aims to provide insights on recent findings indicating the presence of multiple equilibration mechanisms in physical aging of glasses. To this aim, we have investigated a glass forming polyether, poly(1-4 cyclohexane di-methanol) (PCDM), by following the evolution of the enthalpic state during physical aging by fast scanning calorimetry (FSC). The main results of our study indicate that physical aging persists at temperatures way below the glass transition temperature and, in a narrow temperature range, is characterized by a two steps evolution of the enthalpic state. Altogether, our results indicate that the simple old-standing view of physical aging as triggered by the α relaxation does not hold true when aging is carried out deep in the glassy state.

scholarly journals Energy Renormalization for Coarse-Graining the Dynamics of a Model Glass-Forming Liquid

2018 ◽  
Vol 122 (6) ◽  
pp. 2040-2045 ◽  
Author(s):  
Wenjie Xia ◽  
Jake Song ◽  
Nitin K. Hansoge ◽  
Frederick R. Phelan ◽  
Sinan Keten ◽  
...  
Keyword(s):  
Coarse Graining ◽  
Glass Forming ◽  
Model Glass ◽  
Energy Renormalization

The Importance of Transient Nucleation and Non-Equilibrium Viscosity for Glass Formation

1985 ◽  
Vol 57 ◽  
Author(s):  
Kenneth F. Kelton
Keyword(s):  
Steady State ◽  
Metallic Glasses ◽  
Glass Formation ◽  
Volume Fraction ◽  
Molecular Cluster ◽  
Transient Effects ◽  
Glass Forming ◽  
Model Glass ◽  
Transient Nucleation ◽  
Non Equilibrium

AbstractThe process of nucleation and growth in glasses and undercooled liquids is modeled by directly simulating the evolution of the molecular cluster distribution under both isothermal and non-isothermal conditions. Results of that simulation for the nucleation rate during the quench, and for the number of nuclei produced and the volume fraction transformed at the end of the quench are presented. The following three points are discussed: (1) The importance of transient, or non-steady state, nucleation rates on glass formation is assessed by considering three model glass forming systems: lithium disilicate, a relatively good glass former, and two metallic glasses, (Au85Cu15)77Si9Gd14 and Au81Si19. (2) Using experimentally determined values for the steady state nucleation rates and growth velocities for Pd40Ni40P20, it is demonstrated that, in agreement with recent experimental results, this alloy may be cycled at rates on the order of 1 K/sec between the melting and glass transition temperatures without crystallization. Transient effects are shown to be unimportant under these conditions in this system. (3) The effect on glass formation of a non-equilibrium viscosity during the quench due to configurational freezing is evaluated by assuming a phenomenological model for the changing viscosity.

scholarly journals Quantitative relations between cooperative motion, emergent elasticity, and free volume in model glass-forming polymer materials

2015 ◽  
Vol 112 (10) ◽  
pp. 2966-2971 ◽  
Author(s):  
Beatriz A. Pazmiño Betancourt ◽  
Paul Z. Hanakata ◽  
Francis W. Starr ◽  
Jack F. Douglas
Keyword(s):  
Free Volume ◽  
Glass Formation ◽  
Collective Motion ◽  
Configurational Entropy ◽  
Polymer Melt ◽  
Polymer Materials ◽  
Coarse Grained ◽  
Glass Forming ◽  
Cooperative Motion ◽  
Glass Forming Materials

The study of glass formation is largely framed by semiempirical models that emphasize the importance of progressively growing cooperative motion accompanying the drop in fluid configurational entropy, emergent elasticity, or the vanishing of accessible free volume available for molecular motion in cooled liquids. We investigate the extent to which these descriptions are related through computations on a model coarse-grained polymer melt, with and without nanoparticle additives, and for supported polymer films with smooth or rough surfaces, allowing for substantial variation of the glass transition temperature and the fragility of glass formation. We find quantitative relations between emergent elasticity, the average local volume accessible for particle motion, and the growth of collective motion in cooled liquids. Surprisingly, we find that each of these models of glass formation can equally well describe the relaxation data for all of the systems that we simulate. In this way, we uncover some unity in our understanding of glass-forming materials from perspectives formerly considered as distinct.

Influence of Backbone Rigidity on Nanoscale Confinement Effects in Model Glass-Forming Polymers

2013 ◽  
Vol 46 (12) ◽  
pp. 5044-5052 ◽  
Author(s):  
Amit Shavit ◽  
Robert A. Riggleman
Keyword(s):  
Confinement Effects ◽  
Glass Forming ◽  
Model Glass

scholarly journals Crossover to potential energy landscape dominated dynamics in a model glass-forming liquid

2000 ◽  
Vol 112 (22) ◽  
pp. 9834-9840 ◽  
Author(s):  
Thomas B. Schrøder ◽  
Srikanth Sastry ◽  
Jeppe C. Dyre ◽  
Sharon C. Glotzer
Keyword(s):  
Potential Energy ◽  
Energy Landscape ◽  
Glass Forming ◽  
Model Glass ◽  
Potential Energy Landscape
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