Models for rigid and flexible polymers dissolved at low concentration in a dielectric Newtonian fluid and subjected to shear and electric(or magnetic) fields are developed. The rigid polymers are taken to be a rigid spheroid with high aspect ratio and the flexible chains are considered as an elastic dumbbell with a nonlinear spring constant. Specific calculation schemes are developed for transient shear and/or electric fields. Rheo-optical properties such as birefringence and extinction angle are calculated and also interesting components for stress tensor are predicted.