Temporal emission profiles of fluorescein dye-labeled polymers of molecular weight range 4 K to 500 K at two polarization directions parallel and perpendicular to that of the linearly polarized exciting light were measured. The polarization decay time of dye-polymer conjugates increases with molecule weight. Images of an object containing varying molecular weight fluorescein dye-labeled polymers embedded inside turbid media were investigated. The difference image at high polymer molecular weight was found much brighter and clearer than that at low molecular weight. This observation demonstrates that high molecular weight dye-polymer conjugates can be used to enhance the imaging depth and visibility of objects hidden inside scattering media and tissues.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.