The impact of preconditioning constituent materials on the morphology development of organically modified montmorillonite-epoxy nanocomposites is examined to determine the sensitivity of exfoliation to material conditions. In situ synchrotron small-angle X-ray scattering studies were performed to relate the initiation and levels of exfoliated morphologies with various silicate preconditioning processes. Significantly, exfoliation could be achieved in systems initially considered intercalated by preconditioning through epoxy-silicate mixture aging. The resulting morphologies lead to slightly improved toughness. Implications for nanocomposite morphology development models include the necessity of further investigation of the complexities of both local and global morphologies. (C) 2003 Wiley Periodicals, Inc.