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“Sigmoidal” temperature dependence of mechanically induced birefringence in polymers

T. DIMOV1,* , V. VELEV1, I. ILIEV1, CH. D. BETCHEVa2

Affiliation

  1. Konstantin Preslavsky University Shumen, 115 Universitetska street, 9712 Shumen, Bulgaria
  2. University of Chemical Technologyy and Metallurgy, 8 St. Kliment Ohridski blvd., 1756 Sofia, Bulgaria

Abstract

The structural was obtained by birefringence and thermal shrinkage stress relaxation measurements. The PET filaments possess birefringence as a consequence of their formation conditions. The changes in the birefringence were measured after thermal treatment under isothermal conditions, over a large temperature range, using a polarization microscope and a CCD camera. The data were analyzed using Mocha – 1.2 (Jandel-Scientific) software. The glass transition temperature of the samples was defined by thermal shrinkage stress relaxation measurements using the specialized device “Relax-P04”. The results obtained by the two methods are in good agreement..

Keywords

Polyethylene terephthalate, Fibers, Birefringence, Thermal annealing, Glass transition temperature.

Submitted at: Nov. 28, 2006
Accepted at: Feb. 15, 2007

Citation

T. DIMOV, V. VELEV, I. ILIEV, CH. D. BETCHEVa, “Sigmoidal” temperature dependence of mechanically induced birefringence in polymers, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 2, pp. 275-277 (2007)