In this work we present a review of the applications of luminescent probes to follow relaxation processes in polymers. We describe some results using different types of luminescent molecules, such as: benzophenone (phosphorescent molecule), which may be useful to determine motions of small segments of the macromolecules; fluorescein (fluorescent molecule), used to determine the glass transition temperature in polyenthylene glycol 600; and anthracene (fluorescent molecule), which was convenient for studing relaxation process involving macromolecular segments with the same dimension as its longest axis. We also discuss the most important photophysical processes of the luminescent molecule in the solid matrices, related with the polymer relaxation process. Finally, we report results with poly(vinyl chloride) and some of its homopolymer blends, using anthracene as a fluorescent probe.