Band-widths of the Raman stretching modes (ν₁ and ν₂) are calculated as a function of pressure from the anharmonic self energy in solid nitrogen along the 300 K isotherm. Using the Raman shifts of the ν₁ and ν₂ vibrons as the input data, the expression derived from the anharmonic self energy is fitted to the observed bandwidths of those stretching modes from literature in the pressure range of 1 to 31 GPa for the phases of δ (5<P(GPa)<16.5) and ε (above 20.6 GPa) in solid nitrogen. It is shown here that the anharmonic self energy model describes adequately the observed behaviour of the band-widths of the Raman stretching modes studied for the δ and ε phases of solid nitrogen.