N-14 NMR relaxation rates were measured in ternary DDAB water-in-oil microemulsions to investigate structural transitions along oil dilution lines. A two-step model of relaxation was used to estimate the slow correlation times of the surfactant interface. The interpretation of the N-14 slow correlation times in terms of the percolation theory gave critical exponents in agreement with static and dynamic regimes, depending either on the volume fraction of the dispersed phase or on the oil type.