Orientation factor of polypropylene film by infrared dischroism

The orientation factor by infrared dichroism of polypropylene film was compared with the other orientation factors. After the correction of imperfect polarization and the suitable choice of the base line, it was found that infrared dichroism is a reliable indicator of the orientation factor. Orientation factors obtained from the 998 and 842 cm. −1 bands agreed with the x‐ray orientation factor, and that from the 975 cm. −1 band agreed with the optical orientation factor.