<p>An optical storage medium comprises at least one substrate, at least one information layer for storing data and at least one reactive substance. The reactive substance is an inorganic substance causing a chemical reaction with the information layer where H20 is either an initial or a final product of the chemical reaction. The at least one reactive substance may be arranged at least one spot or layer in contact whit the information layer. The readability of the optical storage medium may be adjustably limited by a temporally defined deterioration of the readability, more precisely of the reflectivity of the reflective information layer. The deterioration of the readability may be initiated by the first use of the inventive storage medium by a customer, said in other words the deterioration of the readability may be initiated by heat applied by the laser beam of a disc drive and/or the system temperature of the player. Therefore the deterioration of the readability depends on the time after the first use.</p>
