Controlling Hte Metastable States Of Glasses By External Fields

Glass is a noncrystalline amorphous solid showing glass transition characteristic. It can transform one metastable state to another metastable or stable state in an external field. In glasses, novel functions can be achieved if we control the status, morphology, and distribution of external field-induced structures. This article reviews controlled crystallisation of glass by the external fields, that is, control of ligand field, local symmetry, and energy transfer of active ions etc., by temperature field to achieve efficient broadband near-infrared emission and optical amplification.