scholarly journals Microscopic origin of the logarithmic relaxation in molecular glass-forming liquids

2018 ◽  
Vol 98 (9) ◽  
Author(s):  
Changjiu Chen ◽  
Rithin P. Krishnan ◽  
Kaikin Wong ◽  
Dehong Yu ◽  
Fanni Juranyi ◽  
...  
Keyword(s):  
Glass Forming ◽  
Molecular Glass ◽  
Microscopic Origin

Study of the ?-Mechanical Relaxation in Molecular Glass-Forming Liquids

1997 ◽  
Vol 7 (11) ◽  
pp. 1635-1650 ◽  
Author(s):  
A. Faivre ◽  
L. David ◽  
J. Perez
Keyword(s):  
Mechanical Relaxation ◽  
Glass Forming ◽  
Molecular Glass

Strong Liquid Behavior of Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Forming Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
Ralf Busch ◽  
Andreas Masuhr ◽  
Eric Bakke ◽  
William L. Johnson
Keyword(s):  
Glass Transition ◽  
Melting Point ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Supercooled Liquid ◽  
Glass Transition Region ◽  
Glass Forming ◽  
Liquid Behavior ◽  
Metallic Liquids ◽  
Microscopic Origin

ABSTRACTThe viscosities of the Zr46.75Ti8.25Cu7.5Ni10Be27.5 and the Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass forming liquids was determined from the melting point down to the glass transition in the entire temperature range of the supercooled liquid. The temperature dependence of the viscosity in the supercooled liquid obeys the Vogel-Fulcher-Tammann (VFT) relation. The fragility index D is about 20 for both alloys and the ratio between glass transition temperature and VFT temperature is found to be 1.5. A comparison with other glass forming systems shows that these bulk metallic glass formers are strong liquids comparable to sodium silicate glass. Furthermore, they are the strongest among metallic glass forming liquids. This behavior is a main contributing factor to the glass forming ability since it implicates a higher viscosity from the melting point down to the glass transition compared to other metallic liquids. Thus, the kinetics in the supercooled liquid is sluggish and yields a low critical cooling rate for glass formation. The relaxation behavior in the glass transition region of the alloys is consistent with their strong glassy nature as reflected by a stretching exponent that is close to 0.8. The microscopic origin of the strong liquid behavior of bulk metallic glass formers is discussed.

scholarly journals Fast Vibrational Modes and Slow Heterogeneous Dynamics in Polymers and Viscous Liquids

2019 ◽  
Vol 20 (22) ◽  
pp. 5708 ◽  
Author(s):  
Francesco Puosi ◽  
Antonio Tripodo ◽  
Dino Leporini
Keyword(s):  
Einstein Relation ◽  
Special Focus ◽  
Vibrational Dynamics ◽  
Viscous Liquids ◽  
Dynamical Heterogeneity ◽  
Glass Forming ◽  
Slowing Down ◽  
Molecular Glass ◽  
Distinctive Aspect ◽  
Glass Forming Materials

Many systems, including polymers and molecular liquids, when adequately cooled and/or compressed, solidify into a disordered solid, i.e., a glass. The transition is not abrupt, featuring progressive decrease of the microscopic mobility and huge slowing down of the relaxation. A distinctive aspect of glass-forming materials is the microscopic dynamical heterogeneity (DH), i.e., the presence of regions with almost immobile particles coexisting with others where highly mobile ones are located. Following the first compelling evidence of a strong correlation between vibrational dynamics and ultraslow relaxation, we posed the question if the vibrational dynamics encodes predictive information on DH. Here, we review our results, drawn from molecular-dynamics numerical simulation of polymeric and molecular glass-formers, with a special focus on both the breakdown of the Stokes–Einstein relation between diffusion and viscosity, and the size of the regions with correlated displacements.

Formation of new polymorphs and control of crystallization in molecular glass-formers by electric field

2018 ◽  
Vol 20 (2) ◽  
pp. 925-931 ◽  
Author(s):  
K. Adrjanowicz ◽  
M. Paluch ◽  
R. Richert
Keyword(s):  
Molecular Weight ◽  
Electric Field ◽  
Low Molecular Weight ◽  
Glass Forming ◽  
Molecular Glass ◽  
And Control ◽  
Crystallization Tendency

We show that an electric field is able to modify the crystallization tendency of a low-molecular weight glass-forming liquid.

Viscosity of Amorphous Materials during Glass-Forming: More from the Adam-Gibbs Law

2013 ◽  
Vol 535-536 ◽  
pp. 223-226 ◽  
Author(s):  
H.H. Ruan ◽  
Liang Chi Zhang
Keyword(s):  
Amorphous Materials ◽  
Arithmetic Mean ◽  
Amorphous Selenium ◽  
Macroscopic System ◽  
Glass Forming ◽  
Amorphous System ◽  
Viscosity Variation ◽  
Microscopic Origin ◽  
Viscosity Changes ◽  
Fundamental Mechanism

This study aims to investigate the microscopic origin of viscosity by simplifying an amorphous system to a mixture of many independent atomic subsystems. The response of the macroscopic system is then taken as an ensemble average of the relaxations of such subsystems. The result shows that with the reduction of temperature, the overall viscosity changes from the harmonic mean of the subsystems, which is dominated by the fast relaxations, to the arithmetic mean governed by the slowest relaxation. The successful application of our model to the amorphous Selenium indicates the model captures the fundamental mechanism of the viscosity variation.

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