Free radical crosslinking copolymerization (FCC) of acrylamide (AAm) with various amounts of N,N'-methylenebis(acrylamide) (Bis) is performed at different onset temperatures (T,,,). Variation of temperature, T, and optical transmission, I-tr, are monitored in real time during the gelation process. The decrease in I-tr is modeled by the monomer consumption rate, and the gelation activation energies, DeltaE(G), are measured at each Bis content. During FCC, temperature increases to a certain level then decreases to its initial value as the gelation time increases, which is explained by the heat released during the polymerization process. Decrease in I-tr is attributed to the increase' in scattered light intensity, I-sc, during the formation of interconnected microgels in the system. It is observed that the number of microgels increases as the onset temperature, T-on, is increased. At a given temperature, high Bis content samples produce larger size of microgel particles compared to low Bis content samples.