1-OPTO-THERMAL PROPERTIES OF FIBERS ANNEALING EFFECT ON THE BIREFRINGENCE VARIATIONS OF POLYESTER FIBERS

Polyester(Egyptian) fibers were annealed at constant temperature( 190 degrees C) with different annealing times. Density, crystallinity, mea n square density fluctuation, mechanical loss factor, and molecular or ientation were calculated. Densities and mechanical loss factor were d etermined using an acoustic method. Changes in the molecular orientati on were evaluated from the resulting optical data using the polarizing Pluta interference microscope. Correlation of data obtained by one me thod with another leads to relational changes in optothermal propertie s and in the molecular orientation. Changes of refractive index profil es of annealed PET fibers are provided. Illustrations using graphs and microinterferograms are shown. (C) 1998 John Wiley & Sons, Inc.