VITRIFICATION OF TREHALOSE BY WATER-LOSS FROM ITS CRYSTALLINE DIHYDRATE

Trehalose dihydrate, on careful dehydration below its fusion point, re tains its original crystal facets but becomes X-ray amorphous, an unus ual example of direct crystal-to-glass transformation. From DSC studie s, the glass obtained by this route seems to be of abnormally low enth alpy, but after an initial scan, the normal form of glass transition i s exhibited, with T-g = 115 degrees C, a higher value than previously reported. We give a preliminary thermal and mechanical characterizatio n of this material and find it to be a very fragile liquid. The high T -g is shown to rationalize the exceptionally high water content of the trehalose + water solution that vitrifies at ambient temperature (i.e . T-g = 298 K), and hence helps explain its use by Nature as a desicca tion protectant. The spontaneous vitrification of crystalline material s during desolvation is related to the phenomenology of pressure-induc ed or decompression-induced vitrification of crystals via the concept of limiting metastability.