The three proton resonances in NR corresponding to CH, CH2, and CH3, as has been previously demonstrated, and adapted in Table yield identical coupling, and the spectral average is similar in magnitude to the low-field experiment value. Unexposed SBR yields a spectral average coupling value of about 0.280 kHz. The lowest value is attributed to the phenyl ring due to its motional freedom about the main-chain CH bond. The highest coupling corresponds to the groups at chemical shifts of 1.9 ppm and 1.2-1.8 ppm, coming majorly from the main chain protons of vinyl polybutadiene. This copolymer is also responsible for the spin heterogeneity in the SBR grade considered in this study.