Transient electric birefringence of segmentally flexible macromolecules inelectric fields of arbitrary strength

We study in this work the decay of the electric birefringence from the stea dy-state value to zero when an orienting electric field applied on a macrom olecule is switched off. We consider specifically the case of segmentally f lexible macromolecule with only two subunits and one hinge. Using Brownian dynamics as the predicting tool for the dynamics of the molecule, we have p aid special attention to important aspects such as hydrodynamic interaction , field strength, and orienting mechanism, improving statistics to obtain d ata with very good signal-to-noise ratio, we have found a different behavio r of the induced and permanent dipoles in the relaxation process: the first one can be described independently of the intensity of the field while the second shows a dependence of the field strength. Moreover, the time spectr um shows no dependence on the type of dipole or the field intensity, and am plitudes appear to be essential in characterizing the relaxation of the mol ecule. According to our results, hydrodynamic interaction could be very imp ortant in describing the relaxation times of a molecule, but amplitudes are not affected by this refinement, which should be a very interesting advant age for the application and development of different simplified theories.