A donor-bridge-acceptor fluorophore with extreme sensitivity to environmental influences has been attached covalently to a polyamino crosslinker. It was found that the progress of the crosslinking reaction with an aceto-acetate functionalized polyacrylate dispersion can be monitored from the fluorescence wavelength shift of the fluorophore. Also formation and drying of films applied from the resulting labelled dispersion induces a significant wavelength shift of the fluorescence of the incorporated label.