The melting process of 1-butyl-3-methylimidazolium chloride (bmimC1), a prototype room-temperature ionic liquid, has been studied with fast low frequency Raman spectroscopy. Simultaneous tracing of the lattice vibrations and trans/gauche conformational marker bands reveals that the conformational change in the butyl group occurs a few seconds after the loss of lattice vibrations. This finding indicates that the alkyl chain interaction in bmimC1 is so strong that the butyl conformation hardly changes in the very early stage of melting.