Metastable polymorph formation in a supercooled liquid 2-biphenylmethanol: Luminescence study

We report for the first time on the transformation of the luminescence spectrum of the molecular compound 2-biphenylmethanol (2BPM) on heating from the glassy to liquid phases. The formation of a metastable polymorph after melting of the glassy state has been observed at room temperature. In the luminescence spectra a metastable polymorph manifests itself in the appearance of a new band at 277 nm, which is absent in the spectrum of the stable polymorph. The comparison of the luminescence spectra of the metastable polymorph with that of the glassy phase recorded at 4.2 K shows that the clusters of metastable polymorph are incorporated into the glass structure. In addition temperature-dependent luminescence spectra of both polymorphic forms are presented.