# Glass Transition in Supercooled Liquids with Medium Range Crystalline Order

## TL;DR

This study uses molecular dynamics simulations to explore how medium range crystalline order influences the glass transition, revealing distinct properties and validating a robust method for measuring static length scales.

## Contribution

It demonstrates that glasses with medium range crystalline order have different static and dynamic properties and confirms the Point-to-set method as a reliable tool for measuring static correlation lengths.

## Key findings

- Glasses with MRCO exhibit distinct static and dynamic behaviors.
- The Point-to-set method is validated as an order-agnostic measure of static length scales.
- Differences identified suggest different molecular mechanisms in glasses with and without MRCO.

## Abstract

The origins of rapid dynamical slow down in glass forming liquids in the growth of static length scales, possibly associated with identifiable structural ordering, is a much debated issue. Growth of medium range crystalline order (MRCO) has been observed in various model systems to be associated with glassy behaviour. Such observations raise the question about the eventual state reached by a glass former, if allowed to relax for sufficiently long times. Is a slowly growing crystalline order responsible for slow dynamics? Are the molecular mechanisms for glass transition in liquids with and without MRCO the same? If yes, glass formers with MRCO provide a paradigm for understanding glassy behaviour generically. If not, systems with MRCO form a new class of glass forming materials whose molecular mechanism for slow dynamics may be easier to understand in terms of growing crystalline order, and should be approached in that manner, even while they will not provide generic insights. In this study we perform extensive molecular dynamics simulations of a number of glass forming liquids in two dimensions and show that the static and dynamic properties of glasses with MRCO are different from other glass forming liquids with no predominant local order. We also resolve an important issue regarding the so-called Point-to-set method for determining static length scales, and demonstrate it to be a robust, order agnostic, method for determining static correlation lengths in glass formers.