Electric birefringence (Kerr effect) of polystyrene melts (molecular weight 10 500 and 1050) was measured under low electric field in the frequency range 0.1-10(5) Hz at various temperatures near and above the glass transition temperature. Frequency-temperature superposition was applicable to obtain a composite curve. A weak dispersion of the complex Kerr coefficient was observed in the glass transition zone of the viscoelastic relaxation spectrum. The time evolution of the electric birefringence was found to be in accord with the relaxation of the "strain-induced" birefringence originated by main-chain orientation after step strain.