Anomalous anti-Stokes Raman scattering during epoxy-amine polymerization
In thermal equilibrium the Stokes Raman scatter should always be greater than the anti-Stokes; however, in some rare cases anomalous anti-Stokes Raman scattering (AASR) has been observed. This work presents the first observations of AASR during epoxy-amine polymerization and demonstrates the potenti...
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| Language: | English |
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Elsevier
2025-10-01
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| Series: | Polymer Testing |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0142941825002570 |
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| author | Robert V. Chimenti Samuel E. Lofland |
| author_facet | Robert V. Chimenti Samuel E. Lofland |
| author_sort | Robert V. Chimenti |
| collection | DOAJ |
| description | In thermal equilibrium the Stokes Raman scatter should always be greater than the anti-Stokes; however, in some rare cases anomalous anti-Stokes Raman scattering (AASR) has been observed. This work presents the first observations of AASR during epoxy-amine polymerization and demonstrates the potential to utilize this phenomenon as a means of noncontact heat flow measurement. Even though the phonon population is unbounded, experimental evidence shows that the AASR can be phenomenologically explained from an entropic perspective as negative-absolute-temperature-like behavior. Furthermore, since polymerization is a non-equilibrium thermodynamic process, a statistical physics-based heat flow kinetics model was developed which simultaneously describes the observed AASR and allows for the extraction of the excess phonon population. This excess phonon population was combined with a simplified Debye model for the phonon density of states to calculate an effective heat flow, which closely corresponds to the heat flow measured by isothermal differential scanning calorimetry. |
| format | Article |
| id | doaj-art-c7842e2c1deb44b0bcdcd7e924d88e88 |
| institution | DOAJ |
| issn | 1873-2348 |
| language | English |
| publishDate | 2025-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Polymer Testing |
| spelling | doaj-art-c7842e2c1deb44b0bcdcd7e924d88e882025-08-20T02:57:08ZengElsevierPolymer Testing1873-23482025-10-0115110894310.1016/j.polymertesting.2025.108943Anomalous anti-Stokes Raman scattering during epoxy-amine polymerizationRobert V. Chimenti0Samuel E. Lofland1Department of Physics & Astronomy, Rowan University, 201 Mullica Hill Rd., Glassboro, NJ, 08028, United States; Advanced Materials & Manufacturing Institute (AMMI), Rowan University, 201 Mullica Hill Rd., Glassboro, NJ, 08028, United States; Corresponding author. Department of Physics & Astronomy, Rowan University, 201 Mullica Hill Rd., Glassboro, NJ, 08028, United States.Department of Physics & Astronomy, Rowan University, 201 Mullica Hill Rd., Glassboro, NJ, 08028, United States; Advanced Materials & Manufacturing Institute (AMMI), Rowan University, 201 Mullica Hill Rd., Glassboro, NJ, 08028, United StatesIn thermal equilibrium the Stokes Raman scatter should always be greater than the anti-Stokes; however, in some rare cases anomalous anti-Stokes Raman scattering (AASR) has been observed. This work presents the first observations of AASR during epoxy-amine polymerization and demonstrates the potential to utilize this phenomenon as a means of noncontact heat flow measurement. Even though the phonon population is unbounded, experimental evidence shows that the AASR can be phenomenologically explained from an entropic perspective as negative-absolute-temperature-like behavior. Furthermore, since polymerization is a non-equilibrium thermodynamic process, a statistical physics-based heat flow kinetics model was developed which simultaneously describes the observed AASR and allows for the extraction of the excess phonon population. This excess phonon population was combined with a simplified Debye model for the phonon density of states to calculate an effective heat flow, which closely corresponds to the heat flow measured by isothermal differential scanning calorimetry.http://www.sciencedirect.com/science/article/pii/S0142941825002570Raman thermometryLow-frequency Raman spectroscopyEpoxy polymerizationNon-equilibrium heat flow kinetics |
| spellingShingle | Robert V. Chimenti Samuel E. Lofland Anomalous anti-Stokes Raman scattering during epoxy-amine polymerization Polymer Testing Raman thermometry Low-frequency Raman spectroscopy Epoxy polymerization Non-equilibrium heat flow kinetics |
| title | Anomalous anti-Stokes Raman scattering during epoxy-amine polymerization |
| title_full | Anomalous anti-Stokes Raman scattering during epoxy-amine polymerization |
| title_fullStr | Anomalous anti-Stokes Raman scattering during epoxy-amine polymerization |
| title_full_unstemmed | Anomalous anti-Stokes Raman scattering during epoxy-amine polymerization |
| title_short | Anomalous anti-Stokes Raman scattering during epoxy-amine polymerization |
| title_sort | anomalous anti stokes raman scattering during epoxy amine polymerization |
| topic | Raman thermometry Low-frequency Raman spectroscopy Epoxy polymerization Non-equilibrium heat flow kinetics |
| url | http://www.sciencedirect.com/science/article/pii/S0142941825002570 |
| work_keys_str_mv | AT robertvchimenti anomalousantistokesramanscatteringduringepoxyaminepolymerization AT samuelelofland anomalousantistokesramanscatteringduringepoxyaminepolymerization |