The degradation processes of tris(8-hydroxyquinoline) (Alq(3)) and tris(dibenzoylmethane) mono(1,10-p henanthroline) europium(III) (Eu(dbm)(3)(phen)) thin films are investigated by the use of AFM, photoluminescence and SPR spectroscopy. The plasmonic sensors are operated both in air and nitrogen environments, where they are irradiated with controlled doses of UVA radiation. AFM results don't reveal the formation of heterogeneous phases and crystallization under air exposure. The organic thin films change their refractive index under both types of exposure and act as a protective layer against oxidation for the SiO2/MPTS/metal interface of the plasmonic sensors. SPR measurements reveal a strict correlation between the refractive index increase and quenching of the photoluminescence of the organic thin films. The results are promising for the development of compact plasmonic UVA dosimeters in the surface plasmon coupled emission configuration (SPCE) with lanthanide beta-diketonate complex materials (patent pending). (C) 2018 Elsevier B.V. All rights reserved.