Polymethyl methacrylate (PMMA)/Fe(IO3)(3) nanocomposite thin films are obtained by in situ particle generation in microemulsions and subsequent photopolymerization of a mixture containing methyl methacrylate, trimethylolpropane triacrylate, and crystallized iron iodate (Fe(IO3)(3)) nanorods. Hyper-Rayleigh scattering measurements combined with X-ray diffraction, transmission electron microscopy, and dynamic light scattering are first used to probe in situ the crystallization kinetics of iron iodate nanorods in water-in-oil microemulsions prepared with methyl methacrylate as the oil phase and marlophen NP12 as a surfactant. laser Doppler vibrometry, and Brillouin spectroscopy. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1203-1211, 2013