Brillouin scattering and the glass‐rubber relaxation in amorphous polymers

Patterson, G. D.

doi:10.1002/pol.1975.130130707

Cited by 24 publications

(4 citation statements)

References 12 publications

(3 reference statements)

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“…Brillouin shifts (corrected for q) have been previously reported for a series of PAMAs at their respective glass transition temperatures. For PMMA, the Brillouin splitting was between 10.0 and 10.5 GHz for different samples at T g 41–43. For PEMA, Δω 1 was between 8.8 and 9.0 GHz,22, 42 and for PBMA was between 9.3 GHz for a highly syndiotactic sample25 and 9.9 GHz for a nominally atactic polymer 42.…”

Section: Resultsmentioning

confidence: 98%

“…The Brillouin linewidths at the glass temperature for other PAMAs have been reported. For PMMA, the linewidth was reported over the range between 150 and 250 MHz for different samples 41–43. The linewidth for PEMA was 250 MHz,22, 42 and PBMA was 300 MHz,25, 42 independent of tacticity.…”

Section: Resultsmentioning

confidence: 99%

“…For PMMA, the Brillouin splitting was between 10.0 and 10.5 GHz for different samples at T g . [41][42][43] For PEMA, D! 1 was between 8.8 and 9.0 GHz, 22,42 and for PBMA was between 9.3 GHz for a highly syndiotactic sample 25 and 9.9 GHz for a nominally atactic polymer.…”

Section: Rayleigh-brillouin Spectroscopymentioning

confidence: 99%

“…For PMMA, the linewidth was reported over the range between 150 and 250 MHz for different samples. [41][42][43] The linewidth for PEMA was 250 MHz, 22,42 and PBMA was 300 MHz, 25,42 independent of tacticity. Meier reports a linewidth for PHMA of 500 MHz at the glass temperature.…”

Section: Rayleigh-brillouin Spectroscopymentioning

confidence: 99%

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Evidence for the γ‐relaxation in the light scattering spectra of poly (n‐hexyl methacrylate) near the glass transition

Savin

Patterson

Stevens

2005

J Polym Sci B Polym Phys

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The full range of relaxation processes present in optically pure poly-(n-hexyl methacrylate) (PHMA) was studied using Rayleigh-Brillouin and photon correlation spectroscopy (PCS). Brillouin shifts, linewidths, and Landau-Placzek ratios (LPR) were measured over the temperature range from À11 to 21 8C. The Brillouin splitting and linewidth were consistent with previous studies of PHMA, but the LPR was much lower, indicating that the scattered light primarily comes from intrinsic density fluctuations. Relaxation functions of the same PHMA sample were measured using PCS over the temperature range 0.5-52.5 8C. The average relaxation times calculated from a Williams-Watts fit follow a VFT temperature dependence, with the stretching parameter decreasing with decreasing temperature. The distribution of relaxation times reveals a merging of the and -relaxations over this temperature range, and the temperature dependent width confirms that there are at least two processes with separate temperature dependences. Furthermore, there appears a process at short times in the correlation function window at low temperatures. This upturn at the fastest relaxation times is attributed to the -relaxation present in higher order methacrylate polymers. The effect of the -relaxation is discussed in terms of the dynamic behavior over 12 decades in time. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1504-1519, 2005

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Rayleigh-brillouin Spectroscopymentioning

confidence: 99%

Section: Rayleigh-brillouin Spectroscopymentioning

confidence: 99%

See 2 more Smart Citations

Evidence for the γ‐relaxation in the light scattering spectra of poly (n‐hexyl methacrylate) near the glass transition

Savin

Patterson

Stevens

2005

J Polym Sci B Polym Phys

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Brillouin scattering from polymer films

Patterson¹

1976

J. Polym. Sci. Polym. Phys. Ed.

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SynopsisMany polymers cannot be prepared as clear amorphous blocks suitable for classical light scattering studies. However, most linear polymers can be prepared as films which are somewhat transparent. With the advent of high contrast multipass interferometers, these films can now be studied by Brillouin scattering. This work demonstrates the wide range of polymeric materials that can now be studied by Brillouin spectroscopy.

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Brillouin scattering from amorphous bisphenol‐A polycarbonate

Patterson¹

1976

J. Polym. Sci. Polym. Phys. Ed.

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Brillouin scattering has been studied from amorphous bisphenol‐A polycarbonate in the temperature interval 60–240°C. Both longitudinal and transverse Brillouin peaks are observed over the entire range. The behavior of both types of Brillouin splittings, Δωl and Δωt, in the region of the glass–rubber relaxation is typical of an amorphous polymer. Equilibrium values of Δωl and Δωt were obtained 20°C below the glass‐transition temperature Tg determined at cooling rates of 20°C/hr. Comparison of the present results with previous ultrasonic data reveals a considerable dispersion in the longitudinal phonon velocity below Tg. The origin of the large transverse Brillouin intensities is related to the structure of polycarbonate.

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Brillouin scattering and the glass‐rubber relaxation in amorphous polymers

Cited by 24 publications

References 12 publications

Evidence for the γ‐relaxation in the light scattering spectra of poly (n‐hexyl methacrylate) near the glass transition

Evidence for the γ‐relaxation in the light scattering spectra of poly (n‐hexyl methacrylate) near the glass transition

Brillouin scattering from polymer films

Brillouin scattering from amorphous bisphenol‐A polycarbonate

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