The present invention includes a method of making an edge assembly for an insulating glass unit, the edge assembly including a closed hollow spacer (120), the method comprising (1) dispensing a flowable desiccating matrix (132) formulation onto a portion (158) of the spacer which will be inside the hollow spacer when the spacer has been closed; (2) allowing or causing the formulation to solidify into a solid matrix (132) and to detach from any attachment to the spacer (120); and (3) closing the spacer (120) whereby the detached matrix will be retained within the spacer. The present invention includes a thermoplastic desiccating matrix formulation comprising about 80 to about 30 weight % of the formulation of a thermoplastic material; and about 20 to about 70 weight % of the formulation of an adsorbent component, wherein the adsorbent component includes a moisture adsorbing material and a volatile organic chemical adsorbing material, of which 0-50 weight % of the adsorbent component is the adsorbent of volatile organic compounds; wherein the formulation, when dispensed as a liquid onto an inner surface of an edge assembly and allowed to cool to ambient temperature, forms a solid matrix having an outer surface which does not adhere to the inner surface of the edge assembly.