| Abstract: | Silk fibers (Best Yellow Italian Silk, Ford & Co. Ltd) were annealed at constant temperatures of 100 and 150°C for different times ranging from 1 to 10 h and for different temperatures ranging from 60 to 160 ± 1°C for a constant time of 2 h. Refractive indices and birefringence were measured interferometrically. Two Independent techniques were used to study the optical anisotropy in these fibers. The first technique was to study the effect of annealing on the swelling properties of fibers from its diffraction pattern using a He Ne laser beam. The second is the application of a double-refracting interference microscope. The double-beam technique is considered the most favorable technique in determining the mean re-fractive indices and the double refraction of the annealed samples. The behavior of optical properties at different annealing temperatures and times are discussed. The results obtained clarify that the reorientations occurred due to annealing at different conditions. Microin-terferograms and curves are given for illustration. © 1996 John Wiley & Sons, Inc. |
