Experimental data on the absorbance evolution of an UV irradiated PMMA film containing the TEDBCd CdS precursor published earlier are fitted by the authors' recently published model of precursor-mediated heterogeneous nucleation and growth of nanoparticles in polymer films. Two types of nucleation centers are considered. The centers of the first type are nanoparticles initially existing in the material. The centers of the second type belong to polymer chains. The study shows that the experimental data indicate a wide size distribution of the obtained CdS nanoparticles. For the estimated parameter values, the problem of core−shell nanoparticle growth where the nucleation centers of the first type are nanoparticles of a different nature is considered.