DIRECT EVIDENCE FOR MELTING TRANSITION AT INTERFACE BETWEEN ICE CRYSTAL AND GLASS SUBSTRATE

Melting transition at the interface between ice crystal and glass substrate was directly detected by ellipsometry. At temperatures below -1-degrees-C, a layer with refractive index of 1.42 and thickness of about 10 nm, which has originated from the micro-roughness of the glass surface, was observed. Above -1-degrees-C, a layer with refractive index close to that of bulk water (namely, a quasi-liquid layer) appeared and its thickness rapidly increased as the temperature approached the melting point of ice (0-degrees-C). It is to be emphasized that this result gives direct evidence of the melting transition at the glass-ice interface and the threshold temperature of the melting transition is at least lower than -1-degrees-C.