Dynamics from the Surface to the Bulk in Ultrastable and Liquid-Cooled Oligomeric Glasses
Bibliographic record
Abstract
Ultrastable glasses (USGs) exhibit strikingly different properties from liquid-cooled normal glasses (NGs), yet their molecular dynamics remain poorly understood. Using β-detected NMR of implanted spin-polarized ^{8}Li^{+}, we directly track the depth and temperature dependence of the γ relaxation-phenyl ring twisting-in highly monodisperse atactic styrene oligomers. Near the bulk glass transition temperature T_{g}, USGs show much faster surface dynamics but slower bulk dynamics than an NG. Cooling below T_{g} reveals a sharp crossover at T^{*}, where surface dynamics vitrify on tens to hundreds of nanosecond timescales and become slower than in the bulk. The NG further displays two distinct T^{*} values near the surface, pointing to heterogeneous local structure. Despite these differences, all dynamics obey entropy-enthalpy compensation, suggesting a common molecular mechanism. These results show that preparation and thermal history lock styrene oligomeric glasses into distinct regions of the potential energy landscape, giving rise to fundamentally different glassy dynamics.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".