Related papers: Crossover of aging dynamics in polymer glass: from…
We present time-dependent dielectric loss data at different frequencies for a variety of glass formers after cooling below the glass temperature. The observed aging dynamics is described using a modified Kohlrausch-Williams-Watts law, which…
The glass transition is a long-standing unsolved problem in materials science. For polymers, our understanding of glass-formation is particularly poor due to the added complexity of chain connectivity and flexibility; structural relaxation…
Local segmental relaxation properties of poly(methylmethacrylate) (PMMA) of varying molecular weight are measured by dielectric spectroscopy, and analyzed in combination the equation of state obtained from PVT measurements. The usual…
We investigate the dynamical response of glass-forming systems composed of topologically constrained ring polymers subjected to an instantaneous thermal quench, employing large-scale molecular dynamics simulations. We demonstrate that the…
We use X-Ray Photon Correlation Spectroscopy to investigate the structural relaxation process in a metallic glass on the atomic length scale. We report evidence for a dynamical crossover between the supercooled liquid phase and the…
We use a mixture of a polymer and its dimer to control dynamics in a manner inspired by \emph{pinning} a fraction of the system. In our system of $\alpha$-methyl styrene, where the polymer has a glass transition at higher temperature than…
The effects of the physical aging on the vibrational density of states (VDOS) of a polymeric glass is studied. The VDOS of a poly(methyl methacrylate) glass at low-energy (<15 meV), was determined from inelastic neutron scattering at…
The viscosity of glass-forming liquids increases by many orders of magnitude if their temperature is lowered by a mere factor of 2-3 [1,2]. Recent studies suggest that this widespread phenomenon is accompanied by spatially heterogeneous…
Poly(ethylene terephthalate) (PET) is a semi--crystalline polymer that can be crystallized to different degrees heating from the amorphous state. Even when primary crystallization has been completed, secondary crystallization can take place…
We present results of molecular dynamics (MD) simulations for a non-entangled polymer melt confined between two completely smooth and repulsive walls, interacting with inner particles via the potential $U_{\rm wall}\myeq (\sigma/z)^9$,…
Glassy dynamics was investigated for thin films of atactic polystyrene by complex electric capacitance measurements using dielectric relaxation spectroscopy. During the isothermal aging process the real part of the electric capacitance…
We have examined the nonconventional spin glass phase of the 2-dimensional kagome antiferromagnet (H_3 O) Fe_3 (SO_4)_2 (OH)_6 by means of ac and dc magnetic measurements. The frequency dependence of the ac susceptibility peak is…
In this lecture we review several aspects of the thermal noise properties in two aging materials: a polymer and a colloidal glass. The measurements have been performed after a quench for the polymer and during the transition from a…
Dynamics of thin films of poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA) have been investigated by dielectric relaxation spectroscopy in the frequency range from 0.1Hz to 1MHz at temperatures from 263K to 423K. The…
Aging in a two-dimensional Ising spin model with both ferromagnetic exchange and antiferromagnetic dipolar interactions is established and investigated via Monte Carlo simulations. The behaviour of the autocorrelation function $C(t,t_w)$ is…
Understanding the nature of glass transition, as well as precise estimation of the glass transition temperature for polymeric materials, remain open questions in both experimental and theoretical polymer sciences. We propose a data-driven…
In this study, the effect of alumina and modified alumina nanoparticles in a PMMA/alumina nanocomposite was investigated. To attain this goal, the glass transition behavior of poly methyl methacrylate (PMMA), PMMA/alumina and…
In this paper, we review the general features of the out-of-equilibrium dynamics of spin glasses. We use this example as a guideline for a brief description of glassy dynamics in other disordered systems like structural and polymer glasses,…
The time-dependent response of polystyrene and poly(methyl methacrylate) is studied in isothermal long-term shear creep tests at small strains and various temperatures in the vicinity of the glass transition point. A micromechanical model…
A phenomenon recently coined as ``overaging'' implies a slowdown in the collective (slow) relaxation modes of a glass when a transient shear strain is imposed. We are able to reproduce this behavior in simulations of a supercooled polymer…