Flexible hybrid xerogels bringing together high optical transparency up to 96%, low shrinkage down to 5.5%, very smooth surface (average roughness of about 0.3 nm) and thermal stability up to 200 degrees C were achieved as a result of the optimization of sol-gel preparative method and a new combination of sol-gel precursors. Two types of hybrid materials (hereafter referred, respectively, as urea-silicate and amino-alcohol-silicate gels) were synthesized in this work. The shrinkage and the transparency of these materials have been drastically improved by using two different derived siloxanes (3-isocyanate propyltriethoxysilane and 3-glycidoxypropyltrimethoxysilane) and two amine-terminated polyether precursors with different molecular weights. A drying process was implemented to minimize yellowing of prepared samples. Under these conditions, we were able to efficiently reproduce a well-defined imprinted pattern at materials surface by using an original casting mould. The study of the diffraction characteristics of the obtained grating revealed a good reproducibility of the imprinted grating that shows to be comparable with the original mould. The developed methodology opens the possibility to produce diffraction lenses with a wide range of forms by a simple method based on sol-gel process. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012