Mesoscopic description of the glacial state in triphenyl phosphite from an x-ray diffraction experiment

We present an x-ray-diffraction study performed in the different states of the molecular glass-forming liquid triphenyl phosphite (TPP). Investigations carried out in the apparently amorphous state, the so-called "glacial" state, formed from isothermal aging at different temperatures in the range [210 K, 222 K], confirm previous findings about the structural description of the glacial state in terms of nanocrystallized domains. The very close relationship between the diffraction patterns of the glacial and crystalline states reveals that the glaciation corresponds to an aborted crystallization process. By fitting the whole diffraction pattern of the crystalline phase, all the Bragg peaks can be indexed in a monoclinic unit cell. From this indexation, a structural organization of glacial TPP is given and the domain size can be evaluated for different aging temperatures.