  We report on a study of interaction effects on the polarization of a
disordered two-dimensional electron system in a strong magnetic field. Treating
the Coulomb interaction within the time-dependent Hartree-Fock approximation we
find numerical evidence for dynamical scaling with a dynamical critical
exponent z=1 at the integer quantum Hall plateau transition in the lowest
Landau level. Within the numerical accuracy of our data the conductivity at the
transition and the anomalous diffusion exponent are given by the values for
non-interacting electrons, independent of the strength of the interaction.
