The present study found the time-dependent extraordinary refractive index and birefringence of lyotropic nematic calamitic mesophase for different temperatures during its orientation under magnetic field. Based on the experimental results, the average angle between the mesophase directors and magnetic field was calculated to estimate the orientation dynamics of the mesophase during the director rotation from planar to homeotropic orientations. On the other hand, the textural properties were investigated during the orientation. The ordinary and extraordinary refractive indices were also measured depending on temperature to obtain the orientational order parameter of the mesophase. Using the macroscopic refractive index results, the microscopic polarizability was studied as well.