We show an inorganic-organic hybrid silica gel glass with remarkable femtosecond optical Kerr effect in the order of the time-resolution of the experiment (similar to 200 fs) based on doped lead phthalocyanine. In our materials, self-diffraction of the pumping beam by ultra-fast transient gratings dominates the Kerr signal, ensuring ultrafast response happens. By the replacement of inorganic or polymeric matrix with inorganic-organic hybrid, many practical advantages can be gained. Our results demonstrate a critical role for the design of novel ultrafast optical Kerr shutters in such low-cost silica based-nanocomposites with great flexibility. (c) 2006 Elsevier B.V. All rights reserved.