The properties of a buried epoxy/glass interfacial region were studied by covalently grafting a fluorescent probe to the glass surface. A (dimethylamino)nitrostilbene (DMANS) fluorophore was tethered to a triethoxysilane coupling agent, generating a fluorescently labeled silane coupling agent (FLSCA). The glass surface was coated with a silane layer that was doped with small amounts of FLSCA. The emission maximum from grafted FLSCA was different than when the dye was dissolved in bulk resin, suggesting a different interfacial structure. When the dye was dissolved in bulk cured resin, a red shift in the emission maximum was detected as the resin temperature was increased. A distinct break in the fluorescence maximum vs temperature slope was detected at the glass transition of the bulk resin. The slope became larger at temperatures above T-g. A similar break was observed from grafted FLSCA, suggesting that the grafted dye was sensitive to an apparent glass transition in the buried interfacial region. The temperature of the apparent interfacial transition measured by grafted FLSCA could be lower or higher than the bulk polymer T-g, depending on the initial structure of the grafted silane layer.