Theory of the transient electric birefringence response and its application to relaxation systems

A new formulation of the transient electric birefringence (TEB) response is presented. By using the method of operator expansion for the nonlinear response function, the TEB rise and decay response functions are generally derived for solutions containing two types of polymer molecules: The first is of the polymer molecules with an induced dipole moment (anisotropy in electric polarizability) alone; and the second is of polymer molecules with a permanent dipole moment alone. For the first type of polymer of any main-chain conformation, the TEB rise and decay responses are related with each other by a simple equation, which is the same as in the linear response. In the second type, a simple relation between the two TEB responses is found to hold for particular cases. We find the examples in rod-like and flexible conformations of polymer molecules. TEB responses of rod-like molecules under various confinement conditions are also discussed.