Chemical Applications of the Raman Effect: I. Polymerization

The Raman spectra of methyl methacrylate and similar compounds have been investigated and interpreted. The changes in the molecular constitution on polymerization indicate the disappearance of $\mathrm{a}={\mathrm{C}}_{–}^{–}\begin{array}{c}\mathrm{H}\\ \\ \mathrm{H}\end{array}$ linkage and the like disappearance of the C=C linkage. Lower frequencies appear indicating an increased chain length and a slight decrease in the complexity of the intermediate frequency would seem to indicate an increase in the symmetry of the molecule. The force constants of the more characteristic groups are closer to the cis‐ than the trans‐modification of the isomer. Unlike inorganic glasses, the polymer exhibits at least some sharp lines. These permit an explanation of the continuing structure present throughout the solid and the mechanism by which this structure comes into existence.