Microscopic origin of secondary modes observed in decahydroisoquinoline

Secondary modes in glass-forming liquids can be divided into two classes, i.e. intermolecular processes, known as Johari-Goldstein type and intramolecular processes which probably originates from conformational changes. In this article we present method of identification what molecular motions are responsible for intramolecular secondary mode. We have shown, that intense secondary relaxation (β) observed in decahydroisoquinoline is related with chair to boat interconversion occurring in single cyclohexane type ring. Moreover, fast γ-process observed in dielectric spectra can be interpreted as change of hydrogen linked with heterogenic nitrogen atom from equatorial to axial position.