Optical storage medium

An optical disc comprising:

• a substrate having a first surface and an opposite second surface, a multilayer polymeric film adhered to the first surface of the substrate, and a coverlayer and/or a hard coat layer adhered to an outer surface of the multilayer polymeric film, the multilayer polymeric film including a plurality of coextruded alternating polymeric active data storage layers and polymeric buffer layers, the active data storage layers configured to undergo a permanent induced localized nonlinear or threshold change of optical properties when written by a one photon or multi-photon optical writing process, the buffer layers separating the active data storage layers with sufficient thicknesses to axially confine at least one data voxel written by the optical writing process into a single discrete active data storage layer that is readable by an optical reading device, wherein the buffer layers have an average thickness of 3 μm to about 100 μm, and wherein at least one of the substrate, the multilayer polymeric film, or the cover layer includes at least one tracking feature that provides optical guidance to an optical reading and/or optical writing device during the optical reading and/or optical writing process.