Various synthetic factors that affect the molecular weight, yield, and composition of maleic anhydride (MAH), norbornene (Nb), and tert-butyl 5-norbornene-2-carboxylate (Nb-TBE) terpolymers were investigated. Real-time monitoring via in-situ FTIR spectroscopy of co- and terpolymerizations of MAH with N-b and N-b-TBE was utilized to evaluate the observed rates of varying Nb/NTb-TBE monomer feed ratios. Pseudo-first-order kinetic analysis indicated that the observed rate of reaction (Ie L,) was a strong function of the Nb/Nb-TBE ratio with a maximum of 6.68 < 10(-5) s(-1) for a 50/0/50 Nb/NTh-TBE/MAH monomer ratio and a minimum of 1.13 x 10(-5) s(-1) for a 0/50/50 Nb/NTb-TBE/MA-H ratio. In addition, polymer yields were also observed to be a function of the Nb/Nb-TBE ratio and also decreased with increasing Nb-TBE. Sampling of an Nb/NTb-TBE/MAH (25/25/50 mole ratio) terpolymerization and subsequent analysis using H-1 NMR indicated that the relative rate of N-b incorporation is approximately 1.7 times faster than Nb-TBE incorporation. Also, the observed rate constant of 4.42 x 10(-5) s(-1) calculated using H-1 NMR agreed favorably with the k(obs) determined via in-situ FTIR (3.83 x 10(-5) s(-1)). Terpolymerizations in excess Nb-TBE and in the absence of solvent resulted in relatively high molecular weight materials (M > 20 000) and provided a potential avenue for control of the Nb/N-b-TBE incorporation into the resulting materials.