We have replaced the five Cl atoms in dichlorophosphinylphosphorimidic trichloride with oxyethylene acrylate groups. The monomers obtained were polymerized by taking advantage of the double bonds of the acrylic groups. This was done by ultraviolet irradiation in the presence of a sensitizer. It is found from Fourier transform infra-red,H-1 and P-31 nuclear magnetic resonance spectroscopy and elemental analysis that the obtained substance is the expected one : a new partly inorganic polymer. Volume resistance, dielectric constant and dielectric loss factor were measured over the temperature range from - 10 to + 70 degrees C and compared with those of other phosphazene polymers together with poly(2-hydroxyethyl acrylate). The result seems to show a relation between dielectric properties and hardness of these polymers. In the present polymer system, anomalous dielectric properties were observed for quick-cooled samples. This anomaly is tentatively explained in terms of -OH dipoles frozen in a metastable state in the polymer.