Opto‐thermal properties of fibers: XVII. Structure characterization of cold drawn boiled viscose fibers

A two‐beam interferometric method is used to study the change of optical parameters of cold drawn boiled viscose fibers at different times. A stress–strain device conjugated to the Pluta polarizing interference microscope is used to investigate the dynamical behavior of opto‐mechanical properties at room temperature. Some structural parameters such as the number of molecules per unit volume, the virtual and isotropic refractive indices, the optical orientation factor and angle, the strain and the stress optical coefficients are evaluated. Some mechanical parameters such as, Young's modules, elastic shear modules and the compressibility are calculated over different strain values. Also the number of network chain per unit volume N c , work per unit volume W , average work per chains W ′, reduction in entropy Δ S , and the optical configuration parameter Δα are determined. Also calculation of the constants of Moony–Rivilin equation are given. A systematic study over different wavelengths range extending from 405 to 590 nm was carried out to obtain the dielectric constant at infinity. The obtained results clarify that new reorientations occurred due to cold drawing at different conditions. Empirical formula is suggested to correlate the change in Δ n , f (θ), W , W ′, A , θ, and N c with different draw ratio, and its constants were determined. Microinterferograms and curves are given for illustrations. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1185–1201, 1999