TY - JOUR
T1 - Real time dielectric monitoring of glass transition in n-vinyl pyrrolidone polymerization
AU - Salehli, F.
AU - Bayrak, I.
AU - Nigmatullin, R.
AU - Arbuzov, A.
PY - 2007/12/1
Y1 - 2007/12/1
N2 - Real time dielectric spectroscopy was used for monitoring the dynamics during liquid glass transition in radical bulk polymerization of n-vinyl pyrrolidone. Two different relaxation mechanisms were identified. Initially segmental α-relaxation was dominant. Subsequently, contribution from slower motions became more significant and ε′(tr, ω) underwent maxima in all frequency bands up to 10 MHz. Peak amplitude increased and the occurring time was delayed with decreasing frequency. The slow region dynamics were similar to the dynamics of Chamberlin's domain-like model of glass transition. The glassy phase is formed by a segmental relaxation and a relaxation due to glassy regions. The characteristic relaxation times of slow and segmental motions were well described by a modified Vogel-Fulcher-Tammann relation. The high frequency behavior, associated with the segmental motions, is well described by Havriliak-Negami and Kohlrausch-Williams-Watts formulas, which did not provide satisfactory fittings for the dynamics of slow regions. Both real and imaginary parts of the dielectric data were fully described by a complex dielectric relaxation function, the parameters of which are found by the eigen-coordinates (EC) method.
AB - Real time dielectric spectroscopy was used for monitoring the dynamics during liquid glass transition in radical bulk polymerization of n-vinyl pyrrolidone. Two different relaxation mechanisms were identified. Initially segmental α-relaxation was dominant. Subsequently, contribution from slower motions became more significant and ε′(tr, ω) underwent maxima in all frequency bands up to 10 MHz. Peak amplitude increased and the occurring time was delayed with decreasing frequency. The slow region dynamics were similar to the dynamics of Chamberlin's domain-like model of glass transition. The glassy phase is formed by a segmental relaxation and a relaxation due to glassy regions. The characteristic relaxation times of slow and segmental motions were well described by a modified Vogel-Fulcher-Tammann relation. The high frequency behavior, associated with the segmental motions, is well described by Havriliak-Negami and Kohlrausch-Williams-Watts formulas, which did not provide satisfactory fittings for the dynamics of slow regions. Both real and imaginary parts of the dielectric data were fully described by a complex dielectric relaxation function, the parameters of which are found by the eigen-coordinates (EC) method.
KW - Dielectric properties relaxation
KW - Glass formation
KW - Glass transition
KW - relaxation, electric modulus
UR - http://www.scopus.com/inward/record.url?scp=35548991398&partnerID=8YFLogxK
U2 - 10.1016/j.jnoncrysol.2007.02.073
DO - 10.1016/j.jnoncrysol.2007.02.073
M3 - Article
AN - SCOPUS:35548991398
SN - 0022-3093
VL - 353
SP - 4366
EP - 4370
JO - Journal of Non-Crystalline Solids
JF - Journal of Non-Crystalline Solids
IS - 47-51
ER -