GOLF CLUB HAVING DAMPING TREATMENTS FOR IMPROVED IMPACT ACOUSTICS AND BALL SPEED

A golf club head having a damping treatment, such as a viscoelastic polymer, is disclosed. The viscoelastic polymer may be in contact with the rear surface of a striking face of the golf club head. The viscoelastic polymer may have a tangent of delta peak temperature between −70 degrees Celsius and −20 degrees Celsius at a 1 Hz frequency. An elastic modulus (F), in megapascals (MPa), of the viscoelastic polymer has a relationship to a striking face thickness (t), in millimeters (mm), defined by Ê≤−14{circumflex over (t)}+305. The elastic modulus (E), in megapascals (MPa), of the viscoelastic polymer has a relationship to an effective stiffness (S) of the striking face, in gigapascals per meter (GPa/m), defined by Ê≤−1.16Ŝ+258.33. The viscoelastic polymer may cover a portion of the rear surface of the striking face or may substantially fill a cavity of the golf club head.