Temperature-dependence studies of photorefractive effect in a low glass-transition-temperature polymer composite

1997 ◽  
Vol 82 (12) ◽  
pp. 5923-5931 ◽  
Author(s):  
Bogdan Swedek ◽  
Ning Cheng ◽  
Yiping Cui ◽  
Jaroslaw Zieba ◽  
Jeffrey Winiarz ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Dependence ◽  
Polymer Composite ◽  
Photorefractive Effect

Anomalous Temperature Dependence of Solvent-Enhanced Dye Diffusion In Polymer Films

2002 ◽  
Vol 725 ◽  
Author(s):  
T. Graves-Abe ◽  
F. Pschenitzka ◽  
J.C. Sturm
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Dependence ◽  
Polymer Film ◽  
Light Emitting Diode ◽  
Solvent Vapor ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Driven

AbstractOne promising method to pattern full color polymer Organic Light-Emitting Diode (OLED) displays is to print dye from a pre-patterned organic film onto a spin-cast polymer and then diffuse the dye into the film at room temperature in a solvent vapor environment. This method utilizes the well-known tendency for a polymer film to absorb solvent vapor, which depresses the glass transition temperature of the polymer and dramatically increases diffusion the dye. In this work, we have studied the temperature dependence of this process. The dye coumarin 6 (C6) was transferred onto films consisting of 2-(4-biphenylyl)-5-(4-tert-butylphenyl)- 1,3,4-oxadiazole (PBD) mixed with the polymer poly(9-vinylcarbazole) (PVK). Samples were then placed on a heated stage in a chamber and exposed to acetone vapor to diffuse the C6 into the polymer film. The profile of the diffused dye was determined by depthdependent photoluminescence measurements and Secondary Ion Mass Spectroscopy. We observed that the amount of diffused dye decreased at higher temperatures, in contrast to conventional thermally-driven diffusion. The results are understood by noting that the decrease in the polymer glass-transition temperature and the corresponding rapid increase in dye diffusivity depend on the quantity of solvent absorbed by the polymer, which decreases as the temperature of the polymer is raised.

A Model for Irradiation-Induced Amorphization

1997 ◽  
Vol 504 ◽  
Author(s):  
S. X. Wang ◽  
L. M. Wang ◽  
R. C. Ewing
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Dependence ◽  
Dose Rate ◽  
Volume Fraction ◽  
Ion Irradiation ◽  
Crystallization Rate ◽  
Single Equation ◽  
Sigmoidal Functions

ABSTRACTA model based on cascade melting and recrystallization is derived to describe ion irradiation-induced amorphization. The accumulation of amorphous volume fraction during irradiation is represented in a single equation. Depending on the extent of recrystallization of a subcascade, the amorphous volume accumulation can be described by a set of curves that change from exponential to sigmoidal functions. The parameters (including temperature, cascade size, crystallization rate, glass transition temperature, dose rate) that affect the extent of recrystallization are included in the model. The model also describes the temperature dependence of critical dose for amorphization.

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