X-ray induced phase transitions in 4-((4-(dibutylamino)phenyl)diazenyl)-biphenyl-2,3′,4′-tricarbonitrile

Phase transitions in a glassy film of 4-((4-(dibutylamino)phenyl)diazenyl)-biphenyl-2,3′,4′-tricarbonitrile was initiated by a monochromatic X-ray microbeam with λ = 0.71 Å (MoKα). At the site of the film that was directly impacted by irradiation noticeable morphological changes immediately occurred with subsequent crystal formation. From the site of irradiation, the front of transition of the glassy film into a liquid crystal phase propagated isotropically in all directions. This phenomenon is reproducible and clearly observed in the film prepared by heating the azo compound until melting and cooling it down to room temperature. These results highlight the fact that X-rays can be used as a tool to stimulate phase transitions in glassy azo compounds, which could also give birth to new and unexpected discoveries.