A Brillouin light-scattering investigation of the glass-transition in low molecular weight network glass-formers

1996 ◽  
Vol 87 (6) ◽  
pp. 1439-1457 ◽  
Author(s):  
A. Srinivasan ◽  
F.J. Bermejo ◽  
A. de Bernabé
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Light Scattering ◽  
Low Molecular Weight ◽  
Brillouin Light Scattering ◽  
Network Glass

Glass Transition and Ultrasonic Relaxation in Polystyrene

1996 ◽  
Vol 455 ◽  
Author(s):  
A. Sahnoune ◽  
L. Piché
Keyword(s):  
Molecular Weight ◽  
Relaxation Time ◽  
Glass Transition ◽  
Low Temperatures ◽  
Relaxation Modulus ◽  
Low Molecular Weight ◽  
Relaxation Model ◽  
Fragility Index ◽  
Molecular Weights ◽  
Ultrasonic Relaxation

ABSTRACTWe present measurements of the glass transition and the ultrasonic relaxation modulus in a series of monodisperse polystyrenes. The temperature dependence of the modulus was analyzed using Havriliak-Negami relaxation model (HN) and Vogel-Tammann-Fulcher equation (VTF) for the relaxation time. The results allowed us to determine the fragility index, m, which decreases with increasing molecular weight, Mn. Furthermore, the relaxation time was found to saturate at high molecular weights and varies as Mnp, in the low molecular weight region. The exponent is p≈2 at high temperatures and p ≈ 7 at low temperatures close to Tg.

Supramolecular Structures of Low-Molecular-Weight Polybutadienes, as Studied by Dynamic Light Scattering, NMR and Infrared Spectroscopy

2001 ◽  
Vol 34 (26) ◽  
pp. 9023-9031 ◽  
Author(s):  
Jiří Podešva ◽  
Jiří Dybal ◽  
Jiří Spěváček ◽  
Petr Štěpánek ◽  
Peter Černoch
Keyword(s):  
Molecular Weight ◽  
Infrared Spectroscopy ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Supramolecular Structures ◽  
Low Molecular Weight
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