Wafer bonding using parylene-C to Si, SiO2 and SiN surfaces has recently been shown to enable high pressure-resistant microfluidic devices with metallization and CMOS-integration capability. Here, we report characterization of intermediate parylene-C bonding layer fluorescence (iPBLF) and its use as an on-chip medium for data storage by dynamic programming of iPBLF intensity, using alternating exposure of parylene-C to UV and Green light. This technique allows data on the microfluidic chip to be read, written and erased by a fluorescent microscope and this virtually at no extra cost.