Temporal analysis of grating formation in photopolymer using the nonlocal polymerization-driven diffusion model.

Area of Science:

• Photopolymerization dynamics
• Materials science
• Optical materials

Background:

• The nonlocal polymerization-driven diffusion (NPDD) model accurately predicts spatial frequency cut-off and higher-order grating components in photopolymers.
• Understanding the temporal response of polymer chain growth is crucial for accurate modeling of photopolymerization dynamics.

Purpose of the Study:

• To extend the NPDD model by incorporating the temporal response of polymer chain growth.
• To analyze grating evolution and diffraction efficiency under transient conditions, including cessation of illumination.
• To extract material parameters using experimental data and nonlinear kinetic models.

Main Methods:

• Development of an extended NPDD model incorporating an exponential response function for transient effects.
• Finite element technique for solving the extended model and examining grating evolution.
• Rigorous coupled wave theory applied to independently measured refractive index data.
• Fitting experimental data to nonlinear, ideal, and non-ideal kinetic models for parameter extraction.

Main Results:

• The extended NPDD model successfully accounts for the temporal response during photopolymerization.
• The model predicts the temporal evolution of refractive index modulation and diffraction efficiency.
• Material parameters were extracted by fitting the model to experimental data under various kinetic conditions.

Conclusions:

• The extended NPDD model provides a more comprehensive description of photopolymer grating formation, including transient temporal effects.
• This enhanced model improves the prediction of grating dynamics and diffraction efficiency, crucial for optical material applications.
• The methodology allows for accurate material parameter extraction, aiding in the design and optimization of photopolymer materials.