Diffusionless crystal growth from glass has precursor in equilibrium liquid.

Area of Science:

• Materials Science
• Physical Chemistry
• Crystallography

Background:

• Certain glass-forming liquids exhibit a rapid crystal growth mode (GC) near the glass transition temperature (Tg), extending into the glassy state.
• This GC growth is notably faster than diffusion-limited crystal growth, suggesting unique underlying mechanisms.
• The ROY liquid system, known for its numerous coexisting crystal polymorphs, was utilized to investigate GC growth dynamics.

Discussion:

• This study challenges the established view of GC growth as a phenomenon exclusively emerging near Tg.
• Observations indicate that fast-growing fibers, characteristic of GC growth, are present in the equilibrium liquid state up to approximately 1.15 Tg.
• This suggests GC growth is not a novel mode appearing at Tg but rather a pre-existing characteristic of the viscous liquid.

Key Insights:

• GC growth is not a sudden activation near Tg but an existing feature of equilibrium liquids.
• Fast-growing fibers are identified as the manifestation of GC growth in the liquid state.
• The findings support theories linking GC growth to molecular motions inherent to the glassy state that persist in the liquid.

Outlook:

• Re-evaluation of existing models describing glass-crystal (GC) growth mechanisms is warranted.
• Further research can explore the specific molecular motions responsible for fast-growing fibers in viscous liquids.
• This work provides a new perspective for understanding crystallization phenomena in glass-forming materials.