旋光分散計による分子の配向性に関する研究

抄録

It is shown that anisotropic absorption or dichroism due to molecular orientation can be discussed in terms of optical rotation recorded by means of a spectropolarimeter. When a polyvinyl chloride (PVC) film containing anthracene is stretched, an optical rotatory dispersion curve is obtained at various degrees of elongations corresponding to the absorption spectrum of anthracene (Fig. 2 and 5).
The optical, rotatory power α° at the characteristic absorption frequency is related to the anisotropic optical densities, A_// and A_⊥, respectively in parallel with and perpendicular to the line of stretching as follows,
(1)
where D is called “dichroic difference”.
Taking θ as an average angle between the stretching direction and the transition moment of the absorption band, the orientation function F is given by the relation,
(2)
Thus the values of F and θ can be estimated from the experimental values of α and A_// or A_⊥; the latter two are obtained by the polarized spectra of the stretched film. The orientation function of PVC is obtained by the polarized infrared spectra and compared with that of anthracene at respective degrees of elongation.