UV-vis studies of symmetrically substituted poly(di-n-alkylgermanes) indicate that these polymers exhibit a thermochromic transition at temperatures considerably reduced from that of their polysilane counterparts. Fourier transform Raman spectroscopy using Nd:YAG excitation has been used in conjunction with thermal analysis and conventional Raman spectroscopy to assess the role of the side chains and the germanium backbone in the onset of thermochromism. In order to make a detailed band assignment, a series of Ge oligomers have been synthesized and investigated in both the melt and solid state. Their spectra were obtained using conventional Raman spectroscopy in the visible and the data used to differentiate between backbone and side-chain vibrations. © 1990, American Chemical Society. All rights reserved.