A realistic computer model for polymorphic crystallization (i.e., init
ial and final phases with identical compositions), which includes time
-dependent nucleation and cluster-size-dependent growth rates, is deve
loped and tested by fits to experimental data. Model calculations are
used to assess the validity of two of the more common approaches for t
he analysis of crystallization data. The effects of particle size on t
ransformation kinetics, important for the crystallization of many syst
ems of limited dimension including thin films, fine powders, and nanop
articles, are examined. (C) 1997 Elsevier Science S.A.