We study the transient dynamics of CW intracavity, singly-resonant optical parametric oscillators (ICSRO's). Relaxation oscillations of the 1064-nm pump light are measured, in both the presence and absence of parametric conversion, in a PPLN CW ICSRO pumped intracavity to a Nd:YVO4 laser. The presence of parametric conversion is shown to significantly increase both the damping times and oscillation frequencies of the dynamics; at three times the parametric oscillator threshold, these take values of 200 mu s and 2 MHz, respectively. Oscillation frequencies are shown to be in good agreement with theoretical values. The influence of energy diffusion and thermal lensing are analyzed to account for discrepencies between measured and theoretical damping times. We discuss the implications of the dynamic behavior to the stable-power operation of CW ICSRO's.</p