Impulsive stimulated light scattered from glass‐forming liquids. II. Salol relaxation dynamics, nonergodicity parameter, and testing of mode coupling theory

1995 ◽  
Vol 103 (18) ◽  
pp. 7732-7739 ◽  
Author(s):  
Yongwu Yang ◽  
Keith A. Nelson
Keyword(s):  
Mode Coupling ◽  
Coupling Theory ◽  
Mode Coupling Theory ◽  
Relaxation Dynamics ◽  
Glass Forming

Dynamics in a Nonfragile Glass-Forming Liquid

1996 ◽  
Vol 455 ◽  
Author(s):  
B. Rufflé ◽  
S. Beaufils ◽  
J. Etrillard ◽  
J. Gallier ◽  
B. Toudic ◽  
...  
Keyword(s):  
Structural Relaxation ◽  
Mode Coupling ◽  
Low Frequency ◽  
Large Temperature ◽  
Coupling Theory ◽  
Mode Coupling Theory ◽  
Glass Forming ◽  
Real Change ◽  
Wide Energy ◽  
Fragile Glass

ABSTRACTThe dynamics of Na0.5Li0.5PO3 (Tg = 515 K, Tm = 749 K) a non fragile glass forming liquid has been investigated over a large temperature range (300 − 1000 K.) and in a wide energy window using various experimental techniques. The susceptibility spectra obtained by coherent neutron scattering and depolarized light scattering between 1 and 104 GHz show mainly two contributions: a low frequency vibrational peak, the so-called Boson peak and a quasielastic component, referred to the βfast process in the mode coupling theory (MCT).The data are discussed in relation to the mode coupling theory for the liquid glass transition. In particular, the temperature evolution of the susceptibility height in the βfast region is compatible with a crossover temperature Tc ∼ 620 K which is also deduced from a power law temperature dependence of the structural relaxation timescale. As a secondary βslow process, observed by 31P NMR, decouples from the structural relaxation timescale also below 600 K, a real change in the dynamics seems to occur around Tc ∼ 620 K = 1.2 Tg in this non fragile glass Conning liquid.

scholarly journals Structure and dynamics of glass-forming alloy melts investigated by application of levitation techniques

2019 ◽  
Vol 91 (6) ◽  
pp. 895-910 ◽  
Author(s):  
Dirk Holland-Moritz ◽  
Benedikt Nowak ◽  
Fan Yang ◽  
Andreas Meyer
Keyword(s):  
Mode Coupling ◽  
Short Range ◽  
Structural Information ◽  
Coupling Theory ◽  
Mode Coupling Theory ◽  
Self Diffusion ◽  
Glass Forming ◽  
Input Mode ◽  
Quasielastic Neutron ◽  
Short Range Structure

Abstract In this work results of studies on the short-range order and on the atomic dynamics in different stable and undercooled glass-forming metallic melts are reviewed. In order to undercool the melts deeply below the melting temperature and to avoid chemical reactions of the melts with crucible materials, the samples are containerlessly processed utilizing the electromagnetic or the electrostatic levitation technique. The short-range structure of the melts is studied by neutron diffraction, while the atomic dynamics are investigated by quasielastic neutron scattering. The relationship between short-range structure and atomic dynamics is discussed within the mode coupling theory of the glass transition. We will show that taking the time- and space-averaged structural information provided by measured partial structure factors as an input, mode coupling theory is able to explain the experimental results concerning the activation energies for self-diffusion and the coupling/decoupling behavior of the self-diffusion coefficients of the different alloy components.

Relaxational Dynamics and Strength in Supercooled Liquids from Impulsive Stimulated Thermal Scattering

1995 ◽  
Vol 407 ◽  
Author(s):  
Yongwu Yang ◽  
Laura J. Muller ◽  
Keith A. Nelson
Keyword(s):  
Mode Coupling ◽  
Supercooled Liquids ◽  
Waller Factor ◽  
Time Range ◽  
Coupling Theory ◽  
Mode Coupling Theory ◽  
Relaxation Dynamics ◽  
Debye Waller Factor ◽  
Thermal Scattering

ABSTRACTImpulsive stimulated thermal scattering (ISTS), a time-domain light scattering technique, provides a more than 6-decade time range from sub-ns to many ms. It permits characterization of the structural relaxation dynamics and determination of the relaxation strength or Debye-Waller factor in supercooled liquids, and thus allows testing of the mode coupling theory of the liquidglass transition. ISTS experiments were performed on glass formers salol, butylbenzene, and the molten salt [Ca(N03)]0.4[KNO3]0.6. The relaxational dynamics and the Debye-Waller factorfq=0 were obtained. A square-root anomaly was observed in fq=0 (T) at a crossover temperature Tc for all three materials, consistent with the prediction of mode coupling theory.

Relaxation dynamics in orthoterphenyl: comparing βK from extended mode coupling theory and phenomenological analyses

1998 ◽  
Vol 235-237 ◽  
pp. 254-267 ◽  
Author(s):  
H.Z Cummins ◽  
Y.H Hwang ◽  
Gen Li ◽  
W.M Du ◽  
W Losert ◽  
...  
Keyword(s):  
Mode Coupling ◽  
Coupling Theory ◽  
Mode Coupling Theory ◽  
Relaxation Dynamics
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