High-pressure polymorphism of acetylsalicylic acid (aspirin): Raman spectroscopy

- Raman used to examine high pressure polymorphism of acetylsalicylic acid, aspirin.
- Pressure effects on two polymorphs, Aspirin-I and II, examined to 10 GPa.
- Raman spectra indicted transformation of Aspirin-I to a new Aspirin-III above 2 GPa.
- Aspirin-I to Aspirin-III transition involved rearrangement in acetyl groups.
- Aspirin-II showed no phase change but gradual disordering of structure above 7 GPa.