Experimental study of the response of stilbene to protons (0,8 to 1,8 MeV) indicates a non-linearity in the intensity of the fast components vs energy and a linear relationship for the slow component. It was found for stilbene and anthracene a decreasing intensity of the slow component with increasing particle mass (electrons, protons, alphas). The temperature dependence of both components has been measured between -130Â°C and 20Â°C. A relative increase of the same magnitude, about 20 % has been observed for the fast and the slow emission at low temperature. This paper presents the experimental devices used in these experiments and a discussion of the results in relation to models proposed for the slow emission process (mainly triplet-triplet interaction).