Synthesis and Characterizations of Highly Fluorinated Poly(arylene ether)s for Quadratic Nonlinear Optics
Bibliographic record
Abstract
New highly fluorinated poly(arylene ether sulfone)s (FPAES), poly(arylene ether ketone)s (FPAEK), and poly(arylene ether)s with several types of NLO chromophores as pendant groups were obtained by a polycondensation reaction using very mild conditions. The different polymer structures were designed with the objective to investigate the influence of both the polarity of the chromophore and the nature of the tether between the NLO chromophore and the chain. The resulting copolymers have glass transition temperatures ( T g ’s) varying between 160 and 215 °C, and they are stable up to 280 °C under nitrogen. Although these copolymers are soluble in common organic solvents, cyclohexanone gave the best film quality and was used for the film preparation. After optimization of the poling conditions, the in situ second harmonic generation (SHG) measurements gave nonresonant values of the second-order susceptibilities d 33 ranging from 2 to 8 pm/V, and the SHG signals of the poled polymer films were found to be thermally stable below 130 °C. Although being comparable with the values obtained for similar polymers and chromophores in the literature, d 33 are smaller than those obtained for more conventional NLO polymers like PMMA−Disperse Red One (PMMA-DR1), which was taken as a reference. An unusual drop of the SHG signal during cooling was found in the thermally assisted orientation process. This drop occurred at a characteristic temperature below T g . In this relaxation process which has never been observed, intra- and interchain dipolar interactions are shown to play an important role, which is amplified in the case of chromophores which have their donor group embedded in the main chain, connected by two rigid tethers.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".