[en] In this paper we have determined the behaviour of the protection of the coating of mirrors, using the technique of Electrochemical Impedance Spectroscopy. The system is evaluated with the sodium chloride electrolyte (3% weight) for 0, 5, 24 h and 15 de having the electrolyte introduced in the measuring cell. The paint system used in the protection of mirrors behaves very much like the classical models proposed for the corrosion that a given coating system undergoes in an aggressive medium, according to the results obtained in Electrochemical Impedance Spectroscopy tests for different contact times contact of the system with the sodium chloride electrolyte at weight of 3%. (Author) 13 refs