Shunji Nomura

Characterisation and Assessment of Polymer Orientation

The characterisation of polymer orientation is discussed rigorously in terms of the theory of Krigbaum and Roe by expanding the orientation distribution functions of certain structural units into infinite series of spherical harmonics. The orientation factors averaging the orientation distributions with respect to their moments of any given orders are also introduced in terms of the most general formulae. Also, the assessment of polymer orientation is discussed quantitatively in terms of finite series of spherical harmonics and the truncation errors. The optical anisotropy of bulk polymers is reviewed in a general way, showing how the absorption and emission dichroisms are related to the 2nd and 4th moments of polymer orientation. A graphical representation of the state of uniaxial orientation in the plots of the 2nd-order orientation factor vs the 4th-order orientation factor is proposed for assessing the uniaxial orientation behaviour of noncrystalline structural units with the 4th-order approximation.