A series of sol-gel derived organic-inorganic hybrid materials consisting of organic poly(methyl methacrylate) (PMMA) and inorganic titania (TiO2) were successfully synthesized by using 2-hydroxyethyl methacrylate (HEMA) as coupling agent. In this work, HEMA is first copolymerized with methyl methacrylate monomer at specific feeding ratios by using benzoyl peroxide (BPO) as initiator. Subsequently, the as-prepared copolymer (i.e., sol-gel precursor) is then cohydrolyzed with various contents of titanium butoxide to afford chemical bondings to the forming titania networks to give a series of hybrid materials. Transparent organic-inorganic hybrid materials with different contents of titania are always achieved. Effects of the material composition on the thermal stability, optical properties, and morphology of neat copolymer and a series of hybrid materials, in the form of both coating and free-standing film, are also studied by differential scanning calorimetry, thermogravimetric analysis, UV-Vis transmission spectra, refractometer, and atomic force microscopy, respectively. (C) 2004 Wiley Periodicals, Inc.