A description is given of a disc-shaped rewritable optical information medium having an IPIM stack (2) comprising a phase-change recording layer (4) sandwiched between two dielectric layers (3,5), and a metal mirror layer (6). The thickness of the recording layer (4) increases gradually with increasing radius r. As a result, the complete erasure time CET of recorded marks decreases from the inner radius ri to the outer radius ro. Therefore, at a point closer to the outer radius marks can be recorded at a higher linear speed than at a point closer to the inner radius. This effect ensures that the recording medium can be used for recording at a constant angular velocity (CAV).