Temperature dependence of vibrational motions of thin polystyrene films by infrared reflection-absorption spectroscopy: A single measurement tool for monitoring of glass transition and temperature history

Incorporation of the New anti-Octadecaborane Laser Dyes into Thin Polymer Films: A Temperature-Dependent Photoluminescence and Infrared Spectroscopy Study

“…A sharp decrease in B-H stretching area ( A 2660-2500 ) is detected at 73 °C, 80 °C, and 85 °C, respectively. These temperatures correspond to a temperature domain of β-transition of PS350 as we have described previously [ 26 ] and now in Figure 8 A. All three films were able to retain borane molecules in the structure up to 110 °C, which, in addition, correlates with T g ( T α ) of PS350.…”

“…The drop of the borane cluster PL intensity is probably connected with accelerated diffusion within the film when macromolecular chains rearrange through β- and α-relaxation. Considering that we have already found the polarization-modulation infrared reflection–absorption spectroscopy (PM-IRRAS) method to be a suitable way to describe sub- T g transitions in temperature domains lower than T α of polystyrene [ 26 ], we applied this method to borane cluster instability in polymer thin films when heated. Although the diffusion and/or migration of low molecular species within the polymer matrix of a thin film has been described thoroughly [ 27 , 28 ], the extent and the rate of borane cluster migration out of our studied films was unprecedented.…”

Precise temperature control and rapid heating/cooling of infrared spectroscopy samples with a two-stage thermoelectric device

“…Annealing the poly(styrene) sample at 130 °C for an hour prior to thermal analysis improved variable temperature spectrum measurement reproducibility 26 and minimized spectral features associated with the glass transition. 27 After a short equilibration period at 20 °C, poly(styrene) temperature-dependent changes were characterized by infrared spectroscopy by heating the polymer from 20 to 120 °C at 2 °C min −1 , immediately followed by cooling back to 20 °C at −2 °C min −1 . The spectra obtained at 20 °C before heating, at 120 °C, and after cooling back to 20 °C are overlayed in Fig.…”

“…Poly(styrene) infrared spectrum band maximum shiing to lower wavenumbers with increasing temperature has been described previously. 27,29,30 The green difference spectrum in Fig. 6 represents cumulative spectrum changes caused by applying the heating and cooling program to the sample.…”