MONTE CARLO SIMULATION OF METHANOL GLASS

Monte Carlo simulation studies predict a glass transition in methanol around 180K (experimental T g , 160K). Methanol exists mainly in the form of linear hydrogen bonded polymers with an average of 10 molecules per polymeric unit in the glass at 180K compared to 6 molecules per unit in the liquid at 298K. There is a considerably greater preponderence of the polymeric. species in the glass relative to the liquid. There is a small change in the distribution of the hydrogen bonded species at T g , but a significant breaking down of the polymeric species occurs above 220K. The average coordination number as well as the g min /g max ratios show a change around 220K instead of at T g . The simulated distribution of hydrogen bonded species is comparable to the results obtained from infra-red spectroscopy.