Transient electric birefringence of dilute rigid-body suspensions at low field strengths

This is the authors' abstract. We don't add key points for this paper.

Transient electric birefringence expressions are derived in the Kerr limit of low field strengths for a dilute monodisperse suspension of arbitrarily shaped rigid bodies. A body is characterized by its diffusion tensors, its optical anisotropy tensor, its permanent and instantaneously induced electric dipoles, and its electric charge; no special relation is assumed to hold between these quantities. We specifically allow for charged macromolecules with screw-like shapes which will rotate as well as translate under the exertion of an electric field force. We consider the rise of the birefringence as the field is turned on, its decay following field turn off, and its behavior following reversal of field direction. The birefringence expressions generally involve eight relaxation times during rise and reversal, with only five of these present during decay. The expressions for reversal and decay do not assume prior steady-state alignment; the preexponential amplitudes involved explicitly depend on the duration of the preceding buildup. By varying this duration, different birefringence modes involved in reversal and decay can be selectively weighted according to their relaxation times. Certain cases of symmetry are considered which reduce the number of distinct contributing terms. As an example, we examine the behavior of a long bent rod.