Hydrogen-bonding structures and glass transitions in 1,2-propanediamine mixed with inorganic salts

► Anomalous concentration dependence of Tg was observed in (NaClO4)x(12PDA)1−x. ► Raman spectra indicated the change in the hydrogen-bonding structure. ► Hydrogen bonds between solvent molecules were dominant at low salt concentrations. ► Weak hydrogen bonds were dominant with increasing salt concentrations. ► Anomalous Tg behavior was caused by the interaction crossover.