Abstract
The orientation function of the electric birefringence and dichroism of rodlike polyelectrolytes is derived in a simple case where the induced dipole moment is proportional to the field strength at low fields and becomes constant above a critical field strength. This function is expressed in terms of the field strength E, the electrical polarizability α, and the critical field strength E0. The field strength dependence of the orientation function Φ is represented graphically in the form of Φ vs E* plots or Φ vs γ plots for various values of γ0, where E*≡E/E0, γ≡αE2/2kT, and γ0≡αE20/2kT. With decreasing γ0, the deviation from the classical orientation function for the induced dipole orientation becomes larger.