Shape memory alloy (SMA) wires can be embedded in a host material to alter the stiffness or modal response and provide vibration control. The interaction between the embedded SMA and the host material is critical to applications requiring transfer of loads or strain from the wire to the host. Although there has been a significant amount of research dedicated to characterizing and modeling the response of SMA alone, little research has focused on the transformation behavior of embedded SMAs. In the current work, photoelasticity was used to quantify the internal stresses induced by the actuation of a thin SMA ribbon in a polymer matrix. Through the use of a CCD camera and a frame grabber, photoelastic fringes were digitally recorded at discrete time increments. The stress contours were then analyzed quantitatively as a function of time. A numerical simulation of the embedded ribbon was also carried out using a coupled SMA constitutive model. The thermomechanical model accurately predicted the stress contours throughout the experiment.