%0 Book Section %1 statphys23_0533 %A Thibierge, C. %A Ladieu, F. %A Hôte, D. L' %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K dielectric dynamic glass heterogeneities linear non spectroscopy statphys23 susceptibility topic-9 transition %T Looking for dynamic heterogeneities in glass formers: two experimental methods %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=533 %X Investigating dynamic correlations between molecules in supercooled liquids and glasses is one of the major tasks for experimentalists involved in the glass transition physics. To estimate experimentally the size ($N_corr$) of those dynamic heterogeneities which should grow when temperature goes down to $T_g$, we have developed two experimental methods. The first one consists in measuring accurately the temperature dependence of the linear dielectric susceptibility. It has been shown that $N_corr$ is linked to the square of $d()/dT$ ($\epsilon$: dielectric constant, $T$: temperature, $ømega$: frequency). We measured $\epsilon( )$ every $1K$, $40K$ over $T_g$ for glycerol and every $0.5K$, $20K$ over $T_g$ for propylene carbonate. The evolution of $N_corr$ we deduced shows that it increases by a factor $3$ on our scanned interval. We present here the experimental aspects of this work . The second method links $N_corr$ to the non-linear dielectric susceptibility. We found that our measurement is limited by the non-linear response of standard electronics. Consequently we could only obtain an upper limit on $N_corr$ from our first third harmonic measurements. A new device improves our sensitivity.

@incollection{statphys23_0533, abstract = {Investigating dynamic correlations between molecules in supercooled liquids and glasses is one of the major tasks for experimentalists involved in the glass transition physics. To estimate experimentally the size ($N_{corr}$) of those dynamic heterogeneities which should grow when temperature goes down to $T_{g}$, we have developed two experimental methods. The first one consists in measuring accurately the temperature dependence of the linear dielectric susceptibility. It has been shown that $N_{corr}$ is linked to the square of $d\epsilon (\omega )/dT$ ($\epsilon$: dielectric constant, $T$: temperature, $\omega$: frequency). We measured $\epsilon( \omega )$ every $1K$, $40K$ over $T_{g}$ for glycerol and every $0.5K$, $20K$ over $T_g$ for propylene carbonate. The evolution of $N_{corr}$ we deduced shows that it increases by a factor $3$ on our scanned interval. We present here the experimental aspects of this work . The second method links $N_{corr}$ to the non-linear dielectric susceptibility. We found that our measurement is limited by the non-linear response of standard electronics. Consequently we could only obtain an upper limit on $N_{corr}$ from our first third harmonic measurements. A new device improves our sensitivity.}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Thibierge, C. and Ladieu, F. and H\^ote, D. L'}, biburl = {https://www.bibsonomy.org/bibtex/2b44c36f370289f38e8650733d8d3094c/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {924775f8b4330c6b076964e1d304fcf4}, intrahash = {b44c36f370289f38e8650733d8d3094c}, keywords = {dielectric dynamic glass heterogeneities linear non spectroscopy statphys23 susceptibility topic-9 transition}, month = {9-13 July}, timestamp = {2007-06-20T10:16:22.000+0200}, title = {Looking for dynamic heterogeneities in glass formers: two experimental methods}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=533}, year = 2007 }