エチルベンゼン及び類似分子のガラスおよび過冷却液体ついて，透過光強度とラマン散乱スペクトルを測定した結果，構造緩和にともない屈折率が変化すること，またガラス転移点を境に低振動数分子運動の温度依存性が変化することがわかった。これらの結果と以前に報告したことも含めて，分子性ガラス及び過冷却液体の構造緩和と分子運動について議論する。

Raman and light transmission measurements were curried out for the glass and supercooled liquid of ethylbenzene and related compounds. The change in the refractive index related to the structural relaxation in the glass and thedifference in the temperature dependence of the molecular motion between the glass and supercooled liquid were observed. On the bases of these and other results obtained so far, structural relaxation and molecular motion in the glass and supercooled liquid made of simple molecules will be discussed.