A high-performance optial recording disc has been developed. The recording material is so sensitive that the disc can be recorded and played back by a single optical head using a commercially available laser diode. The recording sensitivity of the disc is enhanced by the unique double-layer structure consisting of a recording layre (Sb-Se compound metal) and a heat absorbing layre (Bi-Te compound metal). In the signal recording process, the recording material changes its physical phase from amorphous to crystalline, when it is heated by laser at 170°C . This phase transition triples the reflectivity of the recording layer. Because the phase transition occurs over a narrow temperature range of about 20 degrees, the pit edge of the recording layer becomes sharp and its pit length is rigidly determined. This ensures a high carrier-to-noise ratio over a wide frequency range. The newly developed disc is, therefore, not only capable of digital recording but also adapt to any pit-length change necessitated by analog video recording. Since the disc recording is facilitated by the changing of the optical characteristics of the recording material, the physical disc form is never affected by laser heat, i.e., neither melted nor evaporated. Therefore, the signal surface can be directly sealed by a protective layer and the disc offers higher storage reliability and greater ease of operation. Direct sealing of the signal surface by protective film also makes a double-sided disc structure possible, enabling the disc to record on both sides. This structure increases the flatness of the disc and enhances its recordability and playability significantly. The new disc will be applied to mass storage as high-performance and massive-information recording medium.