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We report 2 H NMR spin-lattice relaxation times T 1 and spectra of two fragile molecular glass forming liquids, deuterated o-terphenyl-d 14 (OTP) and toluene-d 5, confined in a nanoporous SBA-15 type matrix with a pore diameter of 7.1-nm size. We compare these results with bulk data of several glass formers. The temperature dependence of T 1 allows us to differentiate type A (without secondary β process) from type B glass formers (with β process). We find that the R process of both OTP (type A) and toluene (type B) in confinement is governed by a broad heterogeneous distribution of correlation times, not seen in the bulk. Additionally, there is evidence that the β process in toluene changes under confinement conditions, where it exhibits a distribution of spin-lattice relaxation times that is substantially broadened toward faster times. In contrast, the excess wing for OTP is not altered in confinement.

Using 2 H NMR and high-precision dielectric spectroscopy, we identified in polybutadiene (PB) at low temperatures (20-100 K) a third relaxation process (γ-process) in addition to the R-and β-processes. PB samples with different molecular weights (Mw) exhibit a strongly varying relaxation strength (∆ γ) though no clear-cut relationship is observed between ∆ γ and Mw. Concerning the temperature dependence of the γ-process, the set of samples can be divided into two subsets characterized by different activation energies, where one subset of time constants agrees well with those obtained recently from quasi-elastic light scattering in the melt. From our NMR experiments we conclude that at T < Tg a highly hindered motion (<8°) is responsible for the γ-process, which is difficult to explain by typical conformational changes.