97-09E

Thermodynamics and dynamics of the quasi-one-dimensional disordered ferroelectrics with hydrogen bonds are studied within the framework of disordered Ising model. We obtain thermodynamic potentials, polarization, static and dynamic ${\bf q}$-dependent susceptibilities within the two-site cluster approximation for short-range interactions. Theoretical results are compared to dielectric meusurements in pure and partially deuterated ferroelectrics $Cs(H_{1-x}D_x)_2PO_4$ and $PbH(D)PO_4$. The model predicts the sort ordering in the former crystal: protons and deuterons tend to occupy the nearest neighbour H-bonds.