The dynamics of amorphous poly(2-hydroxypropyl ether of bisphenol-A) (PHR), quenched from the melt, has been investigated by one- and two-dimensional solid-state C-13 NMR spectroscopy. CP/MAS and dipolar decoupled/MAS C-13 NMR spectra from -150 to 180 degreesC give two specific features: (1) below 23 degreesC, resonance lines for C-H carbons of phenylene rings split into two lines; (2) line widths of resonance lines become broad at 110-140 degreesC (30-60 degreesC above the glass transition temperature). Feature 1 indicates that phenylene C-H carbons exist in two magnetically different sites at low temperatures. These two sites are associated with asymmetric conformational states, which maybe produced by OH . . . pi hydrogen bond formation. The coalescence of the resonance lines at elevated temperatures is caused by the pi flip motion of phenylene rings, which corresponds to the gamma relaxation for PHR. The correlation time of the pi flip motion is analyzed by the two-site exchange model and is found to follow the Arrhenius equation. The apparent activation energy is 51 kJ mol(-1) by assuming an inhomogeneous correlation time distribution described by a Kohlrausch-Williams-Watts (KWW) function with an exponent of 0.2. Feature 2 is caused by the so-called motional broadening, which is originated by enhanced segmental motions. This dynamics corresponds to the a relaxation for PHR and can be described by the William-Landel-Ferry (WLF) equation. Two-dimensional (2D) CP/MAS C-13 exchange NMR experiments confirm the existence of flip angle distribution as well as the distribution of correlation times of the phenylene ring pi flip motion. The 2D experiments at -120 degreesC confirm the KWW exponent of 0.2.