[en] The product k p c is the relevant thermophysical parameter for the heating up of material walls in contact with plasma and, apart from the emissivity, it is also the decisive thermal parameter for the quantitative IR thermography; here k, p, and c are the thermal conductivity, density and specific heat capacity, respectively, of the wall material. The Photoacoustic Calorimetry (PAC) provides the diagnostic means to measure this quantity k p c directly. First results of PAC measurements with graphite limiter plates exposed in ASDEX to about 600 discharges are presented and compared to the unused graphite material. Further prospects of the nondestructive photoacoustic techniques in plasma-surface interaction problems are discussed, in relation to coatings/claddings and redeposition layers. (orig.)