Time-resolved synchrotron small-angle X-ray scattering (SAXS) measurements during isothermal crystallization of an associated polymer blend, consisting of one-end-aminated polystyrene (APS) and one-end-sulfonated poly(ethylene glycol (SPES), have been performed. Two different methods of sample preparations were used. In the solvent cast method, the slowly evaporated APS/SPEG/toluene ternary solution should pass through the phase-separated region in the phase diagram, in the freeze-dry method, the solvent benzene was quickly frozen and then evaporated under vacuum, preventing the associated copolymer from dissociation. The freeze-dry sample exhibited similar microphase separation and crystallization behavior as that of the semicrystalline- (hard-) amorphous diblock copolymers with symmetric compositions. The interdomain distance of the freeze-dry sample remained relatively constant when SPEC was being crystallized. On the other hand, both microphase and macrophase separation occurred in the solvent-cast sample, resulting in an appreciably lowered scattered intensity when compared with that of the freeze-dry sample. In quenching from the melt state to 30 degrees C, the long period of the solvent-cast sample increased with time, similar to the behavior of the SPEC homopolymer when it was quenched from its melt state to 42 degrees C. However, this behavior is different from that of the freeze-dry sample which exhibited mainly crystallization behavior in the microphase domain. The difference in the formation of micro- and macrophases of the two samples in the melt state is responsible for the difference in the rate of crystallization of these samples, i.e., the rate of crystallization of homopolymer > that of solvent-cast blend sample > that of freeze-dry blend sample because the freeze-dry sample has the smallest region available for the crystallization of SPEG.