SUPERCOOLED LIQUIDS AND POLYAMORPHISM

We have discovered a solid, apparently amorphous phase of triphenyl ph osphite to which the supercooled liquid converts, a phase distinct fro m both the glass and the crystal. To date, this is the dearest and bes t identified case of a first-order transition from a liquid to another apparently amorphous condensed phase. We discuss this phenomenon in t erms of a recently formulated theory of supercooled liquids that predi cts and naturally incorporates the existence of such low-temperature p hases, thereby suggesting that its existence is a general phenomenon i ntimately connected with the existence and properties of supercooled l iquids. In accord with the theory, we also suggest that although the X -ray scans do not indicate any lattice structure, these apparently amo rphous phases may in fact be defect-ordered structures with large unit cells.