  We study the radiative cooling of polar and metallic nanoparticles immersed
in a thermal bath close to a partially reflecting surface. The dynamics of
relaxation is investigated at different distances from the surface, i.e., in
the near-field and far-field zones. We demonstrate the existence of an
oscillating behavior for the thermal relaxation time with respect to the
separation distance from the surface, an analog of Friedel oscillations in
Fermi liquids.
