The paper deals with an unusual Kerr constant behaviour of comb-like liquid crystalline polysiloxanes in solutions of organic solvents near the critical temperature of stratification. There were observed Kerr constant grows by three orders in magnitude and sign inversion in this thermal region. Pretransitional phenomenon in solutions was explained by formation of a stable aggregates with a high degree of intermolecular ordering. It was shown that a sign of supermolecular Kerr effect is directly connected with the polar properties of polymer mesogenic groups.