• Density dependence of relaxation dynamics in glass formers, and the dependence of their fragility on the softness of inter-particle interactions

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    • Keywords


      Glass; fragility; supercooled liquids etc.

    • Abstract


      Fragility, quantifying the rapidity of variation of relaxation times, is analysed for a series of model glass formers, which differ in the softness of their interparticle interactions. In an attempt to rationalize experimental observations in colloidal suspensions that softer interactions lead to stronger (less fragile) glassformers, we study the variation of relaxation dynamics with density, rather than temperature, as a control parameter.We employ density-temperature scaling, analyzed in recent studies, to address the question.We find that while employing inverse density in place of temperature leads to the conclusion that softer interactions lead to stronger behaviour, the use of scaled variables involving temperature and density lead to the opposite conclusion, similarly to earlier investigations where temperature variation of relaxation dynamics was analysed for the same systems. We rationalize our results by considering the Adam-Gibbs (AG) fragility, which incorporates the density dependence of the configurational entropy and an activation energy that may arise from other propertiesof a glass former.Within the framework of the Adam-Gibbs relation, by employing density temperature scaling for the analysis, we find that softer particles make more fragile glasses, as deduced from dynamical quantities, which is found to be consistent with the Adam-Gibbs fragility.

    • Author Affiliations



      1. Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560 064, India
      2. TIFR Center for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
      3. Indian School of Mines (Indian Institute of Technology) Dhanbad, Jharkhand 826 004, India
    • Dates

  • Journal of Chemical Sciences | News

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      Posted on July 25, 2019

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