EN
Temperature behavior of the optical birefringence in the transitional regions of the incommensurate phase of [N(CH_3)]CuCl_4 was studied. Temperature dependencies of the modulated structure wave vector and of the specific heat in these regions were analyzed. The stochastic mode of the incommensurate modulated structure in [N(CH_3)]MeCl_4 (Me = Cu, Fe) dielectric crystals was discovered.