@article {2152, title = {Surface structure relaxation of poly(methyl methacrylate)}, journal = {Journal of Physical Chemistry B}, volume = {112}, number = {3}, year = {2008}, note = {Li, Qifeng Hua, Rui Cheah, Ignatius J. Chou, Keng C.}, month = {Jan}, pages = {694-697}, abstract = {Surface structure relaxations caused by temperature changes at the free surface of poly(methyl methacrylate) were studied using IR-visible sum-frequency generation (SFG). A polarization-rotating technique was introduced to enhance the sensitivity of SFG for monitoring the surface structure relaxations during a cooling process. A new surface structure relaxation was observed at 67 degrees C. This temperature does not match any known structure relaxation temperatures for the bulk and is 40 degrees C below the bulk glass transition temperature. As expected for a free-surface phenomenon, the surface relaxation temperature was found to be independent of film thickness in the range of 0.1-0.5 mu m.}, isbn = {1520-6106}, url = {://000252484200005}, author = {Li, Q. F. and Hua, R. and Cheah, I. J. and Chou, K. C.} }