The reversible phase transition from hydrochloric-acid-doped ice VI to its hydrogen-ordered counterpart ice XV is followed using differential scanning calorimetry. Upon cooling at ambient pressure fast hydrogen ordering is observed at first followed by a slower process which manifests as a tail to the initial sharp exotherm. The residual hydrogen disorder in H2O and D2O ice XV is determined as a function of the cooling rate. We conclude that it will be difficult to obtain fully hydrogen-ordered ice XV by cooling at ambient pressure. Our new experimental findings are discussed in the context of recent computational work on ice XV.
@article{arxiv.1507.02665,
title = {The complex kinetics of the ice VI to ice XV hydrogen ordering phase transition},
author = {Jacob J. Shephard and Christoph G. Salzmann},
journal= {arXiv preprint arXiv:1507.02665},
year = {2016}
}