Infrared and Raman spectra of polyethyleneglycol dimethylethers in the liquid state

Infrared spectra of ethylene- through heptaethyleneglycol dimethylethers and Raman spectra of ethylene- through tetraethyleneglycol dimethylethers have been measured in the liquid state. Assignments of the vibrational frequencies have been made and the effect of the chain length on the spectra has been discussed with reference to the nature of vibrational modes. The CH2 rocking and the CO and CC stretching modes are appreciably coupled. In the liquid state the internal rotation angles (trans and gauche) about the CC and the CO bonds of the molecular chain are randomly distributed.