In corneal collagen cross-linking (CXL), a treatment often used to stall the progression of keratoconus, a degenerative eye disease, corneal stroma is exposed to UV-light to improve mechanical stiffness by inducing covalent bonding. In clinical practice, a photoreactive riboflavin-solution is applied to the cornea and exposed to 3mW/cm2 of 365nm light for 30 minutes to accelerate cross-link formation. While this technique was recently approved for clinical use, time-evolving changes in CXL are not well understood. If the cornea is over-exposed, UV light may penetrate and damage deeper tissues. If underexposed, insufficient cross-linking may occur. Acoustic Micro-Tapping (AuT) with phase-sensitive OCT can non-invasively probe biomechanical changes in porcine and human cornea at multiple time points during UV-illumination using an air-coupled ultrasound transducer to deliver sufficient displacement on the corneal surface to launch a mechanical wave propagating as a guided mode. Here, guided wave propagation was captured at 100 spatial X-locations over 100 Y-planes to generate a 6 x 6 mm map of wave velocity across the corneal surface. The swept-source OCT system operated in BM mode at a functional frame rate of 16 kHz. In this experiment, corneas were scanned every 2 minutes during 30-minute UV exposure to analyze temporal changes in mechanical wave speed, central corneal thickness, and focusing power. Preliminary results suggest that changes in corneal structure and wave speed over time may infer rates of corneal cross-linking to refine UV illumination protocols and improve clinical outcomes.