Reorientational dynamics in molecular liquids as revealed by dynamic light scattering: From boiling point to glass transition temperature

2013 ◽  
Vol 139 (8) ◽  
pp. 084504 ◽  
Author(s):  
B. Schmidtke ◽  
N. Petzold ◽  
R. Kahlau ◽  
E. A. Rössler
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Boiling Point ◽  
Molecular Liquids ◽  
Reorientational Dynamics

Time and Ensemble Averaged Dynamic Light Scattering in Orthoterphenyl Above and Below the Glass Transition

1996 ◽  
Vol 455 ◽  
Author(s):  
D. L. Sidebottom ◽  
C. M. Sorensen
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Structural Relaxation ◽  
Mode Coupling ◽  
Average Correlation ◽  
Glass Forming ◽  
Ergodicity Breaking

ABSTRACTWhile traditional dynamic light scattering is useful for following structural relaxation in the liquid, in the glassy domain the technique is limited by the ultimate patience of the experimentalist; i.e., the structural relaxation can not be measured when the experimental time scale is less than the structural relaxation time. Nevertheless, we show how useful information regarding structural relaxation can be accessed from light scattering in the glass using a novel ensemble-averaged technique. Dynamic light scattering (DLS) measurements performed on glass forming orthoterphenyl show an inequality between time and ensemble average correlation functions near and below the calorimetrie glass transition temperature, Tg, and hence demonstrate ergodicity breaking. Our ensemble averaged measurements provide a measure of the so-called non-ergodicity parameter, fq, below Tg. Our DLS results for orthoterphenyl indicate that the functional form for fq is consistent with Mode Coupling theory predictions, but occurs at the glass transition temperature, Tg≈243K, rather than at TC≈290K as observed in neutron scattering studies.

Light-Scattering Study of the Glass Transition in Lubricants

1978 ◽  
Vol 100 (3) ◽  
pp. 418-422 ◽  
Author(s):  
M. A. Alsaad ◽  
W. O. Winer ◽  
F. D. Medina ◽  
D. C. O’Shea
Keyword(s):  
Phase Diagram ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Light Scattering ◽  
Brillouin Scattering ◽  
Maximum Pressure ◽  
Scattering Study ◽  
Temperature And Pressure

The sound velocity of four lubricants has been measured as a function of temperature and pressure using Brillouin scattering. A change in slope of the velocity as a function of temperature or pressure allowed the determination of the glass transition temperature and pressure. The glass transition data were used to construct a phase diagram for each lubricant. The data indicate that Tg increased with pressure at a rate which ranged from 120 to 200 C/GPa. The maximum pressure attained was 0.69 GPa and the temperature range was from 25 to 100 C.

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