Measured orientation and internal stress distributions in melt-spun fibers

In this investigation, experimentally measured radial birefringence profiles are compared to internal stress distributions as predicted by a mathematical model. A direct indicator of the degree of molecular orientation, fiber birefringence, is found to correlate well with the stress distributions as calculated from radial temperature variations. In an initial study of glass fibers, no radial birefringence profiles are found, indicating that any residual stresses present are small. In polystyrene fibers, however, large radial variations in birefringence are observed and are shown to be directly related to the calculated internal stresses.