Dielectric measurements are reported on the changes that occur in the nature of the dipole relaxation processes during cure of an epoxy-amine and a diisocyanate-triol system. The epoxy resin forms a vitrified solid in the final cured state, whereas the urethane retains its elastomeric properties. The initial behaviour for the epoxy resin is dominated by ionic conduction processes. Subtraction of the conductivity contribution reveals a dipolar relaxation process, which. is analysed using the Havriliak-Negami (HN) equation. The characteristic exponent 1 - n of the HN equation changes in a similar manner to that found with other epoxy-amine systems. However, the dipolar process in the urethane occurs at very high frequency and a different form of the 1 - n dependence is observed. Sensitivity of the dielectric method for the detection of vitrification and gelation is critically assessed. If the vitrification is allowed to occur, then detection of a gel point may not necessarily be inferred from the dielectric data.