Raman Spectroscopic Studies on Oriented Polymers

The ability of Raman spectroscopic studies on oriented polymers to yield values for both cos 0 and cos 0 has led to its use with polyethylene, atactic 

Purvis and Bower [12] subsequently extended the work, using four additional Raman peaks, aU of which predominantly involve motion of the terephthalyl moiety, to a first approximation. The results suggested that there is no preferred orientation of the plane of the ester group with respect to the plane of the benzene ring in the amorphous phase. They also concluded that the drawing of PET occurs in a similar manner to the extension of a rubber-like network. 

Purvis and Bower [13] also examined drawn specimens of amorphous poly(methyl methacrylate), using four peaks in the Raman spectrum. They were not able to distinguish between two plausible structural models, one essentially linear and the other helical, but they were able to show that their results are consistent with the affine deformational model. 

The success of these measurements prompted a study on drawn specimens of plasticized PVC [14]. This poses problems because of the complexity of the spectrum, which shows overlapping peaks arising from configurational and conformational isomers. In this first study, attention was confined to peaks at 608 and 638 cm specific for long planar syndiotactic sequences, the type of unit 

Several very preliminary reports have appeared in the recent literature, where a dichroic measurement has been attempted, in that spectra have been recorded with no polarization analyser and with the machine direction of the sample set 

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