Proton-decoupled

13C-NMR (operating at 50.3 MHz) is used to determine spin-lattice relaxation time (T1)

Nuclear Overhauser Enhancement (NOE)

line width and Chemical shift of 1

2-polybutadiene at different temperatures in CDCl3 solution and the temperature dependence of molecular motion of 1

2-polybutadiene is studied with these 13C-spin relaxation parameters. It is found that an increase of NOE and of the slope of the plot of line width vs. temperature appears at a range of -10-30℃ and this implied that long-range chain mo-tion is frozen in this temperature range which is consistent with that of glass transition of the sample. The minimum values of curve of nT1 vs. temperature for all carbons occur at about -45℃.