In a method of entering information into an optically writable and readable data storage medium having a polymer film which can be changed locally by heating in order to store information and to which there is assigned an absorber dye (34) which is set up to absorb a write beam (36), at least partly, and to transfer the heat produced in the process, at least partly, locally to the polymer film, first of all the absorber dye is heated locally in a predetermined region of the polymer film in accordance with the information to be entered, specifically by means of a pulsed write beam (36). After that, the absorption properties of the absorber dye (34) are changed by means of light, to be specific preferably by means of a fixing beam (37) which bleaches (38) the absorber dye (34) in the written region of the polymer film.