Yielding, crazing, and fracture of polymers. II. Studies of the retraction of crazed and drawn films

Optical, mechanical, and thermal data on cold‐ and hot‐drawn as well as crazed films of bisphenol A polycarbonate suggest that three separate processes occur during deformation. These processes are a volume change, a preferential orientation of the molecules along the deformation axis, and a configurational change within the molecules (ordering). An attempt is made to correlate these processes with the various types of experimental data. It is suggested that the ordering process is activated by surface, bulk, or external stresses, which are dependent upon molecular weight, processing history, and sample geometry.