Electro-optical properties in solutions of poly-bis-trifluoroethoxyphosphazene (PBFP) have been investigated by means of flow and electric birefringence. The postive experimental value of the shear optical coefficient [n]/[η] of 12 · 10^-10 determines the segmental optical anisotropy of molecules (α₁ - α₂) of 160 · 10^-25 cm³. The values of [n]/[η] and (α₁ - α₂) for PBFP molecules correspond to the optical characteristics of most flexible-chain polymers and indicate that the main chain exhibits considerable coiling. The experimental Kerr constant in PBFP solutions exceeds by three or four orders of magnitude those for flexible-chain macromolecules. The equilibrium values of the Kerr constant and the kinetics of the rise and decay of the Kerr effect show that the orientation of PBFP molecules is determined by large scale motions of the macromolecules. PBFP molecules are characterized by high chain polarity determined by the component of dipole moment of the monomer unit, which is longitudinal with respect to the chain.