Barrier Softening near the onset of Non-Activated Transport in Supercooled Liquids: Implications for Establishing Detailed Connection between Thermodynamic and Kinetic Anomalies in Supercooled Liquids

Abstract

According to the Random First Order Transition (RFOT) theory of glasses, the barriers for activated dynamics in supercooled liquids vanish as the temperature of a viscous liquid approaches the dynamical transition temperature from below. This occurs due to a decrease of the surface tension between local meta-stable molecular arrangements much like at a spinodal. The dynamical transition thus represents a crossover from the low $T$ activated bevavior to a collisional transport regime at high $T$. This barrier softening explains the deviation of the relaxation times, as a function of temperature, from the simple $\log \tau \propto 1/s_c$ dependence at the high viscosity to a mode-mode coupling dominated result at lower viscosity. By calculating the barrier softening effects, the RFOT theory provides a {\em unified} microscopic way to interpret structural relaxation data for many distinct classes of structural glass formers over the measured temperature range. The theory also provides an unambiguous procedure to determine the size of dynamically cooperative regions in the presence of barrier renormalization effects using the experimental temperature dependence of the relaxation times and the configurational entropy data. We use the RFOT theory framework to discuss data for tri-naphthyl benzene, salol, propanol and silica as representative systems.

Submitted to J. Chem. Phys

References in corpus (5)

• The Origin of the Boson Peak and the Thermal Conductivity Plateau in Low Temperature Glasses
• The Intrinsic Quantum Excitations of Low Temperature Glasses
• The solid-liquid interfacial free energy of close-packed metals: hard spheres and the Turnbull coefficient
• Microscopic theory of network glasses
• Droplets and the configurational entropy crisis for random first order transitions

Cited by in corpus (39)

• Theory of Structural Glasses and Supercooled Liquids
• On the Adam-Gibbs-Wolynes scenario for the viscosity increase in glasses
• The frustration-based approach of supercooled liquids and the glass transition: a review and critical assessment
• The Shapes of Cooperatively Rearranging Regions in Glass Forming Liquids
• Theory of Aging in Structural Glasses
• Diverging length scale and upper critical dimension in the Mode-Coupling Theory of the glass transition
• On the surface of glasses
• Thirty milliseconds in the life of a supercooled liquid
• Polymer Glass Formation: Role of Activation Free Energy, Configurational Entropy, and Collective Motion
• Strain localisation above the yielding point in cyclically deformed glasses
• Theory of the Structural Glass Transition: A Pedagogical Review
• On the Strength of Glasses
• First steps of a nucleation theory in disordered systems
• Correlations between vibrational entropy and dynamics in super-cooled liquids
• Metastable States, Relaxation Times and Free-energy Barriers in Finite Dimensional Glassy Systems
• Exact solution for quantum dynamics of a periodically-driven two-level-system
• Determination of onset temperature from the entropy for fragile to strong liquids
• Annealing glasses by cyclic shear deformation
• Are defect models consistent with the entropy and specific heat of glass-formers?
• Polymer Glass-Formation in Variable Dimension
• Finite-dimensional vestige of spinodal criticality above the dynamical glass transition
• Stress distribution and the fragility of supercooled melts
• Electronic structure and the glass transition in pnictide and chalcogenide semiconductor alloys. Part I: The formation of the $pp\sigma$-network
• Random-field Ising model criticality in a glass-forming liquid
• Electronic structure and the glass transition in pnictide and chalcogenide semiconductor alloys. Part II: The intrinsic electronic midgap states
• Charge and momentum transfer in supercooled melts: Why should their relaxation times differ?
• An asymmetry model for the highly viscous flow
• Dynamic heterogeneity of glass-forming liquids in the density scaling regime
• Microscopic theory of the glassy dynamics of passive and active network materials
• Electrodynamics of Amorphous Media at Low Temperatures
• Connecting real glasses to mean-field models
• Self-consistent elastic continuum theory of degenerate, equilibrium aperiodic solids
• Thermodynamics and its correlation with dynamics in a mean-field model and pinned systems: A comparative study using two different methods of entropy calculation
• First-principles study on the specific heat of glass at glass transition with a case study on glycerol
• On the mechanism of the highly viscous flow
• Continuous time random walk concepts applied to extended mode coupling theory: A study of the Stokes-Einstein breakdown
• Temperature-driven narrowing of the insulating gap as a precursor of the insulator-to-metal transition: Implications for the electronic structure of solids
• Emergence of cooperatively reorganizing cluster and super-Arrhenius dynamics of fragile supercooled liquids
• Fragility index of a simple liquid from structural inputs