AbstractThe orientation of the crystals and the amorphouse regions of polyethylene occurring during stretching has been studied using the combined techniques of x‐ray diffraction, infrared dichroism, and birefringence. The state of orientation is expressed in terms of the position of a point on a triangular “orientation diagram.” It is found that the a and b crystallographic axes orient differently. The degree of crystalline orientation is greater at a given elongation for a sample oflower degree of crystallinity than higher. An appreciable amount of amorphous orientation occurs, and appears greater in the more crystalline samples. Orientation oflarger crystalline aggregates has been studied using the light scattering technique and is found to parrallel that of the crystallites. A model consistent with these various types of experimental studies is proposed.