Interferometric Determination of Structural Properties of PEN Highly Oriented Fiber

Abstract

Some optical and structural properties of Poly(ethylene naphthalate-2.6-dicarboxylate), PEN, highly oriented fiber was determined using an automatic variable wavelength interferometric, VAWI, technique. This technique is commonly used jointly with the double refracting polarizing interference microscope designed by Pluta. The microscope was used in two different positions, the subtractive position for determining the spectral dispersion curves of the birefringence and the crossed position for determining the spectral dispersion curves of the refractive indices. The resulting data are utilized to calculate some dispersion and structural parameters such as Cauchy's constants, natural wavelength, dispersion energy, oscillation energy, polarizability per unit volume, dielectric constant, dielectric susceptibility, optical orientation function, and the orientation angle. Microinterferograms are given for illustration.