The development of phase change recording is spurred by the demand of high capacity, low cost and rewritable optical data storage. In phase change optical disk, recording and erasing are achieved by laser heating that induces the crystallographic structural changes in the media. The difference in reflectivities of crystalline and amorphous states determines the information stored. Hence the dependence of optical and thermal effects arising from the laser irradiation on the disk needs to be thoroughly investigated. In today’s competitive marketplace, companies are looking into ways of producing better product at lower cost and shorter development time. Thus the capability of performing interactive computer modeling and analyses of the optical disk becomes inevitable to achieve these ends.