Leuco type thermal rewritable media (LTRM) is based on traditional technology of direct thermal printing. However the introduction of an erasing process brings a rich diversity into its properties and as such requires new understanding of the dynamics of the microscopic structural transitions in order to design practical recording material. The key issue in LTRM is to control its cooling rate during amorphous-tocrystalline transformation. In this report we will discuss the mechanism of the amorphous-to-crystalline transformation in LTRM and will demonstrate the concept of dual color thermal recording by using two different rewritable recording layers with different cooling rate dependency.