The physical and mechanical properties of oriented polymers depend on the crystallinity and molecular orientation that includes the crystalline and the amorphous orientation. These oriented polymers can have various levels of chain orientation ranging from random distribution to highly aligned and the determination of chain orientation is of great interest from both the technical and theoretical points of view. Orientation in both the crystalline and amorphous regions can be measured directly or indirectly using various physical techniques. Crystalline orientation is usually measured using X-ray diffraction and birefringence measurements. Not many physical techniques are available to directly monitor the amorphous orientation of oriented polymers and most studies have resorted to indirect techniques which are of doubtful reliability. The application of infrared and Raman spectroscopy to study the crystallinity and molecular orientation of oriented semicrystalline polymers such as polyolefines, polyamides and polyesters are surveyed in this review.
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