Transient Grating Experiments in Glass-Former Liquids

Bartolini, Paolo; Taschin, A.; Eramo, Roberto; Torre, Renato

doi:10.1007/978-0-387-25558-3_3

Cited by 4 publications

(5 citation statements)

References 45 publications

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“…In nanocomposite materials, the nature of this intermediate dynamics is quite unexpected and cannot be immediately explained using the available TG response models [12]. We can only speculate about its origin.…”

Section: Resultsmentioning

confidence: 92%

Investigation of Relaxation Processes in Nanocomposites by Transient Grating Experiments

Taschin

Bartolini

Sánchez‐Ferrer

et al. 2012

MSF

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We report a comparative study on the photo-elastic and photo-thermal features of two nanocomposites based on MoS2 nanotubes dispersed into two different polyurea elastomeric matrices, which have different crosslinking properties. The time-resolved laser spectroscopic investigation on these nanocomposites by transient grating (TG) experiments has been performed. The relaxation kinetics on a very wide time scale has been measured from nanosecond to hundred of microseconds. The TG data on both pure polymers shows fast acoustic oscillations and a slow thermal decay. No structural relaxation is appearing in the experimental time window. Surprisingly, the presence of nanotubes in both the polymeric matrixes induces intermediate dynamics clearly detected by the TG signal. The features of this unexpected dynamic features recall the structural relaxation typical of glass-formers but its origin is still unclear.

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Section: Resultsmentioning

confidence: 92%

Investigation of Relaxation Processes in Nanocomposites by Transient Grating Experiments

Taschin

Bartolini

Sánchez‐Ferrer

et al. 2012

MSF

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“…Figure 1 shows a schematic view of the grooving with the parameters reported in the caption. The samples were investigated by means of a HD-TRG, although notably transient grating experiments are more usually applied to study transparent materials [16][17][18] in transmission geometry. In the present HD-TRG experiment (fig.…”

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confidence: 99%

“…2), two infrared laser pulses, obtained by dividing a single pulsed laser beam (pulse duration ∼20 ps, wavelength 1064 nm and a total intensity at the sample's surface of a few µJ), are temporally and spatially overlapped on the sample surface where they interfere to produce an impulsive and spatially periodic variation of the temperature due to metal absorption. The experimental details about the laser systems and acquisition procedure can be found elsewhere [18,19].…”

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confidence: 99%

“…6. The HD-TRG signal decays mainly due to two processes: the intrinsic acoustic damping rate and the geometrical variation of the counter-propagating SAWs features [18]. The main geometrical effect is due to the SAW-packets escaping from the probed area at the speed v g , lowering the time of temporal overlap of the SAW which is known as the "walk-off" time 3 , τ .…”

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confidence: 99%

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Evidence of slow acoustic surface waves on a 1D phononic surface by a pulsed laser spectroscopic technique resolved in time and space

Malfanti¹,

Taschin²,

Bartolini³

et al. 2012

EPL

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We report the investigation of surface acoustic waves (SAWs) propagating on a 1D phononic surface (PS) by the heterodyne-detected transient reflecting grating technique. A suitable experimental configuration enables the excitation of traveling SAWs with variable wave numbers and the measurement of their propagation with temporal and spatial resolution. Using the full characterization of the band diagram of this PS, as reported previously (Malfanti I., Taschin A., Bartolini P., Bonello B. and Torre R., J. Mech. Phys. Solids, 59 (2011) 2370), we studied the dispersion properties of the SAWs as the wave number approaches the Brillouin zone edge. SAW-packet group velocities show a clear slowing-down process approaching the BZ edge, with a measurable minimum velocity of about 140 m/s

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“…Following the usual TG signal convention, the sign of the data is chosen positive for a negative change of density[37].…”

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confidence: 99%

Temperature of maximum density of water in hydrophilic confinement measured by transient grating spectroscopy

Taschin¹,

Cucini²,

Bartolini³

et al. 2010

EPL

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We report heterodyne detected transient grating measurements on water confined in the hydrophilic porous glass Vycor7930 in the range of temperature from −15 to 90 • C. With this experiment we are able to obtain the temperature of the water maximum density by measuring the temperature when the water thermal expansion coefficient vanishes. We found, similarly to what is already reported in the literature in hydrophobic confinement, that the temperature of the maximum density shifts to lower temperatures. We obtain this maximum at −1 ± 1 • C. No experimental evidence of a shift of the temperature of maximum density in hydrophilic systems has been previously reported.

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Transient Grating Experiments in Glass-Former Liquids

Cited by 4 publications

References 45 publications

Investigation of Relaxation Processes in Nanocomposites by Transient Grating Experiments

Investigation of Relaxation Processes in Nanocomposites by Transient Grating Experiments

Evidence of slow acoustic surface waves on a 1D phononic surface by a pulsed laser spectroscopic technique resolved in time and space

Temperature of maximum density of water in hydrophilic confinement measured by transient grating spectroscopy

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