In this podcast episode, MRS Bulletin's Sophia Chen interviews Zahra Fakhraai of the University of Pennsylvania on her group's research to better understand how a substance condenses into glass. They studied the liquid–liquid phase transition in vapor-deposited thin films of N,N0-bis(3-methylphenyl)-N,N0-diphenylbenzidine (TPD). They discovered a new high-density supercooled liquid phase in glasses deposited in the thickness range of 25-55 nm. Their findings could lead to more precise theoretical descriptions of glasses.