Shrinkage Measurements of UV-Curable Adhesives

Curing processes of any adhesive are always accompanied with its volumetric change, known as polymerization shrinkage. Although the relative volume change is usually less than a few percent, shrinkage is particularly problematic for applications where sub‐mm positioning is required, such as bonding of micro‐optics or optical fibers. We present a simple method to precisely measure the linear shrinkage of UV‐curable adhesives based on optical distance measurement. The method allows to observe in situ the dynamics of the shrinkage process.