Free volume from positron lifetime and pressure–volume–temperature experiments in relation to structural relaxation of van der Waals molecular glass-forming liquids

2010 ◽  
Vol 22 (23) ◽  
pp. 235104 ◽  
Author(s):  
G Dlubek ◽  
M Q Shaikh ◽  
K Rätzke ◽  
M Paluch ◽  
F Faupel
Keyword(s):  
Free Volume ◽  
Structural Relaxation ◽  
Positron Lifetime ◽  
Van Der Waals ◽  
Glass Forming ◽  
Molecular Glass

Free Volume Changes in Bulk Amorphous Alloys During Structural Relaxation and in the Supercooled Liquid State

1998 ◽  
Vol 554 ◽  
Author(s):  
C. Nagel ◽  
K. Rätzke ◽  
E. Schmidtke ◽  
F. Faupel
Keyword(s):  
Free Volume ◽  
Metallic Glasses ◽  
Structural Relaxation ◽  
Amorphous Alloys ◽  
Excess Volume ◽  
Positron Lifetime ◽  
Supercooled Liquid ◽  
Mechanical Tests ◽  
Volume Changes ◽  
Shallow Traps

AbstractVolume changes in Zr46.7Ti8.3Cu7.5Ni10Be27.5 and Zr 65Al7.5Ni10Cu17.5 bulk metallic glasses have been observed by positron annihilation and density measurements. At low cooling rates excess volume of the order of 0.1 % is quenched in both glasses. Isothermal relaxation kinetics below the glass transition temperature obey a Kohlrausch law with exponents of β≈(0.3 ± 0.1). Structural relaxation is not accompanied by embrittlement, as indicated by simple mechanical tests. The outer surface plays a crucial role in annealing of excess volume, which can be restored by annealing above Tg. The observed free volume changes are at variance with the behavior of a perfectly strong glass. The temperature dependence of the positron lifetime is discussed in terms of thermal detrapping from shallow traps.

Free volume of an oligomeric epoxy resin and its relation to structural relaxation: Evidence from positron lifetime and pressure-volume-temperature experiments

2007 ◽  
Vol 75 (2) ◽  
Author(s):  
Günter Dlubek ◽  
Jürgen Pointeck ◽  
Muhamad Qasim Shaikh ◽  
E. M. Hassan ◽  
Reinhard Krause-Rehberg
Keyword(s):  
Epoxy Resin ◽  
Free Volume ◽  
Structural Relaxation ◽  
Positron Lifetime

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
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