Glass-transition temperature: Relation between low-frequency dynamics and medium-range order

1995 ◽  
Vol 51 (13) ◽  
pp. 8606-8609 ◽  
Author(s):  
Claire Levelut ◽  
Nabil Gaimes ◽  
Ferial Terki ◽  
Gérard Cohen-Solal ◽  
Jacques Pelous ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Low Frequency ◽  
Range Order ◽  
Temperature Relation ◽  
Medium Range Order ◽  
Medium Range

PROPERTIES AND STRUCTURE OF Ag-DOPED As2Se3 GLASSES

2007 ◽  
Vol 16 (01) ◽  
pp. 49-57 ◽  
Author(s):  
CONGJI ZHA ◽  
ANITA SMITH ◽  
AMRITA PRASAD ◽  
RONGPING WANG ◽  
STEVE MADDEN ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Raman Band ◽  
Glass Structure ◽  
Low Frequency ◽  
Glass Network ◽  
Scanning Calorimetry ◽  
Covalent Bonds ◽  
Frequency Shifts

Ag -doped As 2 Se 3 glasses were prepared by the melt-quenching method and the influence of silver doping on the glass structure and optical properties was studied using Raman and UV-Vis-IR spectroscopy and differential scanning calorimetry. For Ag concentrations less than 15 at%, introduction of Ag into As 2 Se 3 glasses mainly leads to the formation of Ag-Se covalent bonds, resulting in destruction of the glass network. This manifests itself by a decrease in the glass transition temperature and low frequency shifts in the As-Se Raman band. When the Ag concentration was higher than 25 at%, some Ag atoms exist in the glass matrix as coordinative bonds, resulting in a slight increase in the glass transition temperature and high frequency shifts in the Raman peaks. The relationship between the glass structure and properties is discussed.

scholarly journals Boson peak, elasticity, and glass transition temperature in polymer glasses: Effects of the rigidity of chain bending

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Naoya Tomoshige ◽  
Hideyuki Mizuno ◽  
Tatsuya Mori ◽  
Kang Kim ◽  
Nobuyuki Matubayasi
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Low Frequency ◽  
Peak Frequency ◽  
Boson Peak ◽  
Polymer Chains ◽  
Coarse Grained ◽  
Elastic Response ◽  
Bending Rigidity

AbstractThe excess low-frequency vibrational spectrum, called boson peak, and non-affine elastic response are the most important particularities of glasses. Herein, the vibrational and mechanical properties of polymeric glasses are examined by using coarse-grained molecular dynamics simulations, with particular attention to the effects of the bending rigidity of the polymer chains. As the rigidity increases, the system undergoes a glass transition at a higher temperature (under a constant pressure), which decreases the density of the glass phase. The elastic moduli, which are controlled by the decrease of the density and the increase of the rigidity, show a non-monotonic dependence on the rigidity of the polymer chain that arises from the non-affine component. Moreover, a clear boson peak is observed in the vibrational density of states, which depends on the macroscopic shear modulus G. In particular, the boson peak frequency ωBP is proportional to $$\sqrt{G}$$G. These results provide a positive correlation between the boson peak, shear elasticity, and the glass transition temperature.

A Possible Mechanism For Atomic Transport in Amorphous Metals

1997 ◽  
Vol 481 ◽  
Author(s):  
Leon D. Van Ee ◽  
Barend J. Tthijsse ◽  
Jilt Sietsma
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Diffusion Process ◽  
Structural Changes ◽  
Low Frequency ◽  
Vibrational Modes ◽  
Atomic Transport ◽  
Localized Vibrational Modes ◽  
Irreversible Nature

ABSTRACTThe diffusion process at a temperature just below the glass-transition temperature is studied in a computer model of amorphous Ni81B19. The observed diffusion events cause structural changes that are highly localized and are correlated with low-frequency localized vibrational modes. The excitation of such a mode can result in a “jump”, which is identical to the diffusion event. The jump has a cooperative character involving some tens of atoms and can be of a reversible or of an irreversible nature.

Low-frequency dynamics and medium-range order in vitreous silica

1996 ◽  
Vol 53 (5) ◽  
pp. 2411-2418 ◽  
Author(s):  
F. Terki ◽  
C. Levelut ◽  
M. Boissier ◽  
J. Pelous
Keyword(s):  
Low Frequency ◽  
Vitreous Silica ◽  
Range Order ◽  
Medium Range Order ◽  
Medium Range

Revealing ordering and structural changes at glass transition

2013 ◽  
Vol 1520 ◽  
Author(s):  
Michael I. Ojovan
Keyword(s):  
Glass Transition ◽  
Amorphous Materials ◽  
Structural Changes ◽  
Range Order ◽  
Medium Range Order ◽  
Disordered Structure ◽  
Bonding System ◽  
Liquid Transition ◽  
Medium Range

ABSTRACTOrdering types in the disordered structure of amorphous materials and structural changes which occur at glass-liquid transition are discussed revealing medium range order and reduction of topological signature of bonding system.

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