scholarly journals Ultraslow Relaxation Process of Static Light Scattering Intensity by Boron Oxide above the Glass Transition Temperature

2015 ◽  
Vol 03 (07) ◽  
pp. 75-80
Author(s):  
N. A. Bokov
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Light Scattering ◽  
Relaxation Process ◽  
Boron Oxide ◽  
Static Light Scattering ◽  
Scattering Intensity ◽  
Light Scattering Intensity

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.

Nonequilibrium Fluctuations of Light Scattering Intensity in the Neighborhood of the Phase Transition Temperature

2020 ◽  
Vol 128 (1) ◽  
pp. 74-77
Author(s):  
A. N. Alekseev ◽  
L. Yu. Vergun ◽  
Yu. F. Zabashta ◽  
V. I. Kovalchuk ◽  
M. M. Lazarenko ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Light Scattering ◽  
Phase Transition Temperature ◽  
Nonequilibrium Fluctuations ◽  
Scattering Intensity ◽  
Light Scattering Intensity

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.

Brillouin Light Scattering Determination of the Glass Transition in Thin, Freely-Standing Poly(styrene) Films

1995 ◽  
Vol 407 ◽  
Author(s):  
J. A. Forrest ◽  
K. Dalnoki-Veress ◽  
J. R. Dutcher ◽  
A. C. Rowat ◽  
J. R. Stevens
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Light Scattering ◽  
Guided Waves ◽  
Brillouin Light Scattering ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Glass Substrates

ABSTRACTWe have used Brillouin light scattering (BLS) to measure the glass transition temperature of thin, freely-standing poly(styrene) (PS) films. The freely-standing films were prepared by spincoating solutions of PS in toluene onto glass substrates, annealing the supported films in vacuum, and then using a water surface transfer technique to place the films across a 3 mm diameter orifice. Ellipsometry measurements of similar floated films transferred to Si(001) wafers allow the determination of the film thicknesses. Atomic force microscopy measurements revealed that the films have an rms roughness of less than 10 A˚. With the freely-standing films placed in an optical furnace, we performed BLS measurements of the films using a high-contrast, multipassed, tandem Fabry-Perot interferometer. We obtained a reliable, reproducible measure of the glass transition temperature, Tg, from the large changes in the frequencies of the thermally-excited, viscoelastic, film-guided waves within the PS films as the films were heated above Tg. BLS results for bulk PS and a 1800 A˚ thick, freely-standing PS film are presented. We find the same glass transition temperature for the 1800 A˚ thick film as the bulk PS sample. This Tg value is the same as that obtained using differential scanning calorimetry (DSC).

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