Reaserch data for manuscript: The role of ring geometry and rigidity in the glassy dynamics of cyclic dimethylsila crowns under elevated pressure

This study uncovers the relaxation behavior of three cyclic dimethylsila crown ethers (DMS11C4, DMS14C5, and DMS17C6). From dielectric spectra, two distinct relaxation processes are consistently observed: a structural α-relaxation associated with cooperative molecular rearrangements and a secondary β-relaxation that exhibits the characteristics of a JG process, as predicted by the CM at ambient pressure. It is essential to verify whether these JG characteristics are preserved under compression, since the β-relaxation processes do not fully superimpose under varying T and p conditions. Although a modest pressure-induced enhancement and a slight frequency shift are observed at isochronal conditions, these variations remain within acceptable range so they are consistent with the preservation of JG behavior.The dataset contains raw dielectric loss spectra collected for all three samples. Calorimetric measurements have also been added.