Relationship between activation volume and polymer matrix effects on photochromic performance: bridging molecular...

Area of Science:

• Materials Science
• Photochemistry
• Polymer Science

Background:

• Photochromic compounds offer reversible color change for applications like ophthalmic lenses.
• Their performance degrades in polymer matrices due to structural changes during photochromism.
• Bridged imidazole dimers are fast photoswitch molecules with high photochromic quantum yield and durability.

Purpose of the Study:

• To investigate the pressure effects on the photochromic properties of bridged imidazole dimers.
• To establish activation volume as a predictor for structural changes during photochromism.
• To guide the development of photochromic compounds for polymer applications.

Main Methods:

• Investigated pressure effects on bridged imidazole dimers' photochromic properties.
• Utilized activation volume for thermal back-reaction as a measure of structural change.
• Analyzed the relationship between activation volume and photochromic performance in a polymer matrix.

Main Results:

• Smaller activation volumes correlate with reduced impact of surrounding matrix on photochromic reactions.
• Activation volume effectively predicts the degree of structural change during photochromism.
• Bridged imidazole dimers with smaller activation volumes maintain efficient photochromic reactions in polymers.

Conclusions:

• Smaller activation volumes are crucial for maintaining efficient photochromic reactions in polymer matrices.
• Activation volume serves as a key parameter for designing robust photochromic materials.
• Findings offer insights for developing advanced photochromic compounds for ophthalmic lenses and pressure-sensitive materials.