Poly(ethylene terephthalate) fibers and films produced by varying process parameters, such as production speed and medium, temperature and rate of drawing, were annealed at temperatures between 100 and 250-degrees-C in the free-to-shrink and constant-length conditions. The as-spun, as-drawn, and drawn and annealed samples were etched in 40% aqueous methylamine at room temperature for 4 h. The etch patterns were examined on a scanning electron microscope and were found to be related mainly to residual stress and its distribution in the samples and thereby to sample morphology. The studies clearly bring about the important role played by the processing history.