Opto-thermal properties of fibers 8. Optical and mechanical parameters variations on cold drawn thermally treated nylon 6-6 fibers

Refractive indices and birefringence changes with strain produced by differ ent stresses in annealed and unannealed nylon 6-6 fibers (Promilan, Toray I ndustries Inc. Japan) were measured interferometrically. Calculations were carried out to determine the strain optical coefficient, the orientation fa ctor, the orientation angle, the number of molecules per unit volume, the i sotropic refractive index and the virtual refractive index. The effect of t he draw ratio on the refractive index profile was studied. The generalized Lorentz-Lorenz equation given by de Vries has been used to compare the resu lts obtained by Hermans' optical orientation function. (C) 1999 Elsevier Sc ience Ltd. All rights reserved.