The nucleation, growth and orientation of lead zirconate titanate thin films prepared from organometallic precursor solutions by spin coating on (111) oriented platinum substrates and crystallized by rapid thermal annealing was investigated. The effects of pyrolysis temperature, post-pyrolysis thermal treatments, excess lead addition, and Nb dopant substitution are reported. The use of post pyrolysis oxygen anneals at temperatures in the regime of 350-450 deg C was found to strongly effect the kinetics of subsequent amorphous-pyrochlore perovskite crystallization by rapid thermal annealing. It has also allowed films of reproducible microstructure and textures (both (100) and (111)) to be prepared by rapid thermal annealing. It is suggested that such anneals and pyrolysis temperature affect the oxygen concentration/average Pb valence in the amorphous films prior to annealing. The changes in Pb valence state then affect the stability of the transient pyrochlore phase and thus the kinetics of perovskite crystallization. Nb dopant was also found to influence the crystallization kinetics. 28 refs., 18 figs.