Using a Kretschmann configuration‐based setup, surface‐enhanced Raman scattering (SERS) experiments have been performed on a monolayer of Nile blue. The experiment has been optimized to achieve reproducible conditions. Laser excitation resulted in a fast decay of the Raman line intensities ending at a stable signal level. We have analyzed this intensity variation mode specifically. The Raman deactivation rate was found to be different for different vibrational modes where high‐wavenumber vibrations showed slower decay than the group of low‐wavenumber modes. SERS spectra were obtained excluding the contribution of this deactivation process for different angles of incidence of the exciting laser beam. The variation of the surface plasmon excitation in the thin silver film coated onto the prism surface of the Kretschmann configuration resulted in drastically different relative enhancements of the different Raman modes pointing to a major contribution of the chemical enhancement mechanism in the single‐layer SERS experiment. The enhancement was found to be mode‐specific. High‐wavenumber modes showed a stronger enhancement than the low‐wavenumber group. Copyright © 2016 John Wiley & Sons, Ltd.