High pressure Raman experiments on Boron Nitride multi-walled nanotubes show that the intensity of the vibrational mode at ~ 1367 cm-1 vanishes at ~ 12 GPa and it does not recover under decompression. In comparison, the high pressure Raman experiments on hexagonal Boron Nitride show a clear signature of a phase transition from hexagonal to wurtzite at ~ 13 GPa which is reversible on decompression. These results are contrasted with the pressure behavior of carbon nanotubes and graphite.
@article{arxiv.cond-mat/0603223,
title = {Comparative High Pressure Raman Study of Boron Nitride Nanotubes and Hexagonal Boron Nitride},
author = {Surajit Saha and D. V. S. Muthu and D. Golberg and C. Tang and C. Zhi and Y. Bando and A. K. Sood},
journal= {arXiv preprint arXiv:cond-mat/0603223},
year = {2007}
}