Optical properties, spectroscopy birefringence

The results of studying the optical properties (birefringence, IR and UV dichroism), x-ray, spectroscopy, NMR, and EPR (with specially introduced paramagnetic probes) methods are usually used for estimating the order parameter [40]. The so-called guest-host effect is a widely used method (cf. Chapter 8). 

Every property of an interface that can be optically probed can, in prmciple, be measured with the SEA. This may include infonnation obtainable from absorption spectroscopy [M], fluorescence, dicln-oism, birefringence, or nonlinear optics [43], some of which have already been realized. 

It has been demonstrated that there is a direct relationship between the fiber mechanical properties and the molecular orientation (Figure 1). A similar relationship exists between the processing conditions, molecular orientation and mechanical properties. It has been shown that a combination of optical birefringence and the infrared spectroscopy techniques can be used for the measurement of molecular orientation. The results show that for a set of fiber samples, the 841 cm" infrared peak can be confidently used for the estimation of crystalline orientation averages. The 973 cm" peak can be separated using curve fitting procedures into 972 and 974 cm" components and the latter component can be used to estimate the amorphous orientation averages. 

Kejcwords amorphous orientation, crystalline orientation, Herman s orientation factor, infrared spectroscopy (IR), IR band assignment, optical birefringence, orientation, structure-property relationships in fibers, X-ray diffraction... 

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