Differential scanning calorimetry (DSC) of polymer 5 revealed a glass transition temperature of (Tg) of 48.1 ºC and no observable melting transition (Tm). The lower Tg than reported is likely due to the shorter chain length of the polymer and its atactic nature, which was confirmed by C NMR analysis. Thermogravimetric analysis (TGA) of the polymer showed a relatively high decomposition temperature of 300 ºC, which was lower than the reported 395-396 ºC of polymer initiated by 11. Mechanistic investigation of hydrazinium-initiated polymerization was attempted through in situ NMR reaction monitoring. Diffusion filtered NMR acertained that the aldehyde signal, and more importantly, the styrenyl chain-end used to estimate degree of polymerization, belonged to the polymer. Chain length measurement obtained by 1 H NMR analysis was comparable to the values obtained from differential refractive index GPC (GPC-DRI) referenced to polystyrene standard and light scattering GPC (GPC-LS) (dn/dc measured in THF= 0.2149, DPGPC-DRI = 49, DPGPC-LS = 50, DPNMR = 65).