Spectroscopic and calorimetric investigation of cyclohexanol in different orientational states

The thermal analysis and infrared (IR) spectroscopy were used to study cyclohexanol irreversible transformations from an orientationally disordered plastic state to metastable III and then to a stable II crystalline phase. It was found that the orientational glass transition in cyclohexanol occurs at Tg similar to 163.5 K. Solid-solid transition from orientationally disordered phase I to metastable phase III occurs at 195 K. Crystal phase III nucleates at Ta = 203 K and converts into phase I at T = 233.7 K. The stable crystal phase II is formed by nucleation at 213 K. It converts into phase I at T = 250 K. It is shown by IR spectroscopy that the phase transitions in solid cyclohexanol are correlated with conformational changes in the cyclohexanol molecule.