Most embedded optical waveguide biosensors require low dielectric optical material. The prerequisites for such applications include the selection of an appropriate material and effective bio-functionalization. Spin-on glass (SOG) is one of the preferred polymers that can be easily deposited. Further, the chemical properties of the polymer make it amenable for bio-functionalization. This paper reports a detailed study of a protocol for immobilization of antibodies on SOG for possible immunobiosensor applications. The effect of silanization at different pH values on the number of free and usable amine sites was quantified by fluorimetry. Contact angle measurements, ellipsometry, AFM, and fluorescence microscopy was used for assessing the surface properties at various stages of preparation, functionalization and biomolecule immobilization. (C) 2008 Elsevier B.V. All rights reserved.